Dimensionally stable geopolymer composition and method

ABSTRACT

A method for making geopolymer cementitious binder compositions for cementitious products such as concrete, precast construction elements and panels, mortar, patching materials for road repairs and other repair materials, and the like is disclosed. The geopolymer cementitious compositions of some embodiments are made by mixing a synergistic mixture of thermally activated aluminosilicate mineral, calcium sulfoaluminate cement, a calcium sulfate and a chemical activator with water.

CROSS-REFERENCE TO RELATED APPLICATIONS

This claims the benefit to U.S. Provisional Application No. 61/639,803,filed Apr. 27, 2012 and U.S. Provisional Application No. 61/653,696,filed May 31, 2012.

FIELD OF THE INVENTION

This invention relates generally to cementitious compositions containingaluminosilicate based geopolymers that can be used for a variety ofapplications. In particular, the invention generally relates to suchcementitious compositions which offer properties that are desirable interms of setting times, exothermal dimensional stability, reducedoverall material shrinkage upon curing and other such desirableproperties.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 6,572,698 to Ko discloses an activated aluminosilicatebinder containing aluminosilicates, calcium sulphate and an activatorcontaining alkali metal salts is disclosed. The aluminosilicates areselected from a group consisting of blast furnace slag, clay, marl andindustrial by-products, such as fly ash, and has an Al₂O₃ contentgreater than 5% by weight. Blast furnace slag is present in an amountless than 35% by weight, and cements kiln dust (CKD), in an amount offrom 1 to 20% by weight, is added to the mixture as an activator.

U.S. Pat. No. 4,488,909 to Galer et al discusses cementitiouscompositions including Portland cement, high alumina cement, calciumsulfate and lime. The cementitious composition includes Portland cement,high alumina cement, calcium sulfate and lime. Pozzolans such as flyash, montmorillonite clay, diatomaceous earth and pumicite may be addedup to about 25%. The cement composition includes about 14 to 21 wt %high alumina cement.

U.S. Pat. No. 6,869,474 to Perez-Pena et al, discusses cementitiouscompositions for producing cement-based products such as cement boards.This is achieved by adding an alkanolamine to hydraulic cement such asPortland cement, and forming a slurry with water under conditions thatprovide an initial slurry temperature of at least 90° F. (32° C.).Additional reactive materials may be included such as high aluminacement, calcium sulfate and a pozzolanic material such as fly ash.

U.S. Pat. No. 7,670,427 of Perez-Pena et al, discusses extremely fastsetting of cementitious compositions with early-age compressive strengthfor producing cement-based products such as cement boards achieved byadding an alkanolamine and a phosphate to a hydraulic cement such asPortland cement, and forming a slurry with water under conditions thatprovide an initial slurry temperature of at least 90° F. (32° C.).Additional reactive materials may be included such as high aluminacement, calcium sulfate and a pozzolanic material such as fly ash.

US published patent application No. US 2010-0071597 A1 of Perez-Penadiscloses formulations using fly ash and alkali metal salts of citricacid such as sodium citrate to form concrete mixes. Hydrolaulic cementand gypsum can be used up to 25 wt % of the formulation, although theiruse is not preferred. The activated fly ash binders described in thisapplication may interact with the traditional foaming systems used toentrain air and thereby make lightweight boards.

U.S. Pat. No. 5,536,310 to Brook et al disclose a cementitiouscomposition containing 10-30 parts by weight (pbw) of a hydraulic cementsuch as Portland cement, 50-80 pbw fly ash, and 0.5-8.0 pbw expressed asa free acid of a carboxylic acid such as citric acid or alkali metalsalts thereof, e.g., tripotassium citrate or trisodium citrate, withother conventional additives, including retarder additives such as boricacid or borax.

U.S. Pat. No. 6,641,658 to Dubey discloses a Portland cement basedcementitious composition which contains 35-90% Portland cement, 0-55% ofa pozzolan, 5-15% of high alumina cement and 1 to 8% of insolubleanhydrite form of calcium sulfate in place of the soluble conventionallandplaster/gypsum to increase the release of heat and decrease settingtime despite the use of high amounts of pozzolan, e.g., fly ash. Thecementitious composition can include lightweight aggregates and fillers,superplasticizers and additives such as sodium citrate as a reactionretarder.

U.S. Pat. No. 7,618,490 B2 to Nakashima et al. discloses a sprayingmaterial comprising one or more of calcium sulfoaluminate, calciumaluminosilicate, calcium hydroxide, a source of fluorine and Portlandcement concrete. Calcium sulfate may be added as anhydrous orhemihydrate gypsum.

U.S. Pat. No. 4,655,979 to Nakano et al. discloses a process for makinga cellular concrete using calcium silicate based cement, alkali metalretarder, calcium sulfoaluminate (CSA) cement and an optional calciumsulfate that can be added to the concrete composition.

US 2008/0134943 A1 to Godfrey et al. discloses a waste encapsulationmaterial composed of at least one sulphoaluminate salt of an alkalineearth metal with calcium sulphate, and optional inorganic filler such asblast furnace slag, pulverized fuel ash, finely divided silica,limestone, and organic and inorganic fluidizing agents. Preferably atleast one sulphoaluminate salt of an alkaline earth metal comprisescalcium sulphoaluminate (CSA). A suitable composition may, for example,comprise at least one sulphoaluminate salt of an alkaline earth metal incombination with gypsum and pulverized fuel ash (PFA), wherein about 86%of the gypsum particles have a particle size of less than 76 um, androughly 88% of the PFA particles have a particle size below 45 um. Oneexample comprises 75% (70:30 CSA:CaSO4.2H2O); 25% Pulverized Fuel Ash;water/solids ratio 0.65.

U.S. Pat. No. 6,730,162 to Li et al. discloses dual cementitiouscompositions including a first hydraulic composition having 2.5% to 95wt. % C₄A₃S which is chemical notation wherein C═CaO, S═SiO₂, A=Al₂O₃(in other words calcium sulfo-alumina) and 2.5 to 95 wt. % a hemihydrateand/or an anhydrite of calcium sulfate. Sulfoalumina cements orferroalumina cements are examples of cements that contain C₄A₃S. It mayalso include mineral filler additives selected from the group consistingof slag, fly ash, pozzolan, silica soot, limestone fines, limeindustrial by-products and wastes.

Chinese published application CN 101921548 A to Deng et al. discloses acomposition of sulfoaluminate cement made from 90-95 wt sulfoaluminateclinker and anhydrous gypsum, quartz sand, fly ash from wasteincineration, hydroxypropyl methylcellulose ether, redispersible gluepowder and fiber. The sulfoaluminate clinker and anhydrous gypsum meetsthe standard of sulfoaluminate cement, i.e. GB20472-2006.

Korean published application KR 549958 B1 to Jung et al. discloses acomposition of alumina cement, CSA, gypsum, calcium citrate, andhydroxylcarboxylic acid.

Korean published application KR 2009085451A to Noh, discloses acomposition of powdered blast furnace slag, gypsum and CSA. The gypsumcan have an average particle size of 4 micron or less.

KR 2009025683 A discloses powder type waterproof material used forconcrete and mortar, is obtained by pulverizing cement, anhydrousgypsum, silica powder, waterproof powder, fly ash, calciumsulfoaluminate type expansion material and inorganic binder.

Korean published application KR 2010129104 A to Gyu et al. disclosescomposition for blending shotcrete, comprises (in wt. %): metakaolin(5-20), calcium sulfoaluminate (5-20), anhydrous gypsum (20-45), and flyash (30-50).

There is a need for dimensionally stable cementitious materialscontaining geopolymeric compositions that provide reduced shrinkageafter curing, improved initial and final temperature behavior,controlled and/or optimized setting times, improved strength and otherproperties beneficial to the use of such materials in buildingconstruction, formed cementitious products and other applications, suchas cementitious structures, cementitious structural elements, and moldedcementitious products, as well as methods for preparing such materialsand forming such structures, elements, and products.

SUMMARY OF THE INVENTION

The present invention provides improved geopolymer cementitiouscompositions and methods for making such compositions having at leastone, and in many instances more than one, highly desirable property suchas significantly improved dimensional stability during and after curing;improved and modifiable initial and final setting times; extendedworking times; modified temperature generation during mixing, settingand curing; and other improved properties as discussed herein. In many,if not all, of such embodiments, the improved properties are providedwithout significant (if any) loss in early age compressive strength,final compressive strength or other strength properties. Someembodiments, in fact, provide a surprising increase in early age andfinal compressive strength.

The improved properties of those and other embodiments of the inventionprovide distinct advantages over prior geopolymeric binders, such as flyash based binders, as well as other cementitious binders that maycontain a significant geopolymer content. In some preferred embodiments,the geopolymer cementitious compositions of the invention are formedfrom solutions or slurries of at least water and one or morecementitious reactive components in a dry or powder form. Thecementitious reactive components comprise effective amounts of thermallyactivated geopolymer aluminosilicate materials, such as fly ash; calciumsulfoaluminate cements; and calcium sulfates. One or more alkali metalchemical activator, such as an alkali metal salt of citric acid, or analkali metal base, also is added to the solutions, either in a dry formto the reactive powder, or as a liquid addition to the slurry.Optionally, the slurry or solution may incorporate other additives suchas water reducing agents, set accelerating or retarding agents,air-entraining agents, foaming agents, wetting agents, lightweight orother aggregates, reinforcing materials, or other additives to provideor modify the properties of the slurry and final product.

In many preferred compositions of the invention, the cementitiousreactive components in their dry or powder form comprise about 65 toabout 97 weight percent thermally activated aluminosilicate mineral suchas fly ash, about 2 to about 30 weight percent calcium sulfoaluminatecement, and about 0.2 to about 15 weight percent calcium sulfate, basedupon the total dry weight of all the cementitious reactive components.In preferred compositions of invention, the cementitious reactivecomponents comprise calcium sulfoaluminate cement in about 1 to about200 parts by weight relative to 100 parts by weight of thermallyactivated aluminosilicate mineral.

In other embodiments, a blend of two or more types of calciumsulfoaluminate cement and calcium aluminate cement may be used, and theamounts and types of calcium sulfoaluminate cements and calciumaluminate cements can vary depending upon their chemical composition andparticle size (Blaine fineness). The Blaine fineness of calciumsulfoaluminate cement in such embodiments and other embodimentspreferably is greater than about 3000, more preferably greater thanabout 4000, even more preferably greater than 5000, and most preferablygreater than about 6000.

In some preferred embodiments, the amount of alkali metal chemicalactivator is from about 0.5% to about 10% by weight based upon the totaldry weight of the cementitious reactive materials. More preferably, therange of alkali metal chemical activator about 1% to about 6% by totalweight of the cementitious reactive materials, preferably about 1.25% toabout 4%, more preferably about 1.5% to about 3.5%, and most preferablyabout 1.5% to 2.5%. Sodium citrate and potassium citrate are preferredalkali metal acid activators, although a blend of sodium and potassiumcitrate can also be used. Alkali metal bases, such as alkali metalhydroxides, and alkali metal silicates also may be used depending on theapplication and the needs of that application.

These and other preferred embodiments of the invention, unlike prior flyash geopolymer compositions, are formulated to provide geopolymercementitious compositions that are dimensionally stable and resistant tocracking upon setting and hardening under both unrestrained andrestrained conditions. For example, the short term free shrinkage ofcertain preferred embodiments of the invention typically is less thanabout 0.3%, preferably less than about 0.2%, and more preferably lessthan about 0.1%, and most preferably less than about 0.05% (measuredafter initial set and within 1 to 4 hours of mixing). In such preferredembodiments, the long term shrinkage of the compositions during curingalso typically is less than about 0.3%, more preferably less than about0.2%, and most preferably less than about 0.1%.

For additional control regarding the dimensional stability and shrinkagein those embodiments, the amount of calcium sulfoaluminate cement isabout 2.5 to about 100 parts by weight relative to 100 parts by weightof the thermally activated aluminosilicate mineral, more preferablyabout 2.5 to about 50 parts by weight relative to 100 parts by weight ofthe thermally activated aluminosilicate mineral, and most preferablyabout 5 to about 30 parts by weight relative to 100 parts by weight ofthermally activated aluminosilicate mineral. For embodiments where thecontrol on dimensional stability as indicated by the material shrinkageis of importance, the amount of alkali metal activator more preferablyranges from about 1 to about 3% by total dry weight of the cementitiousreactive materials (i.e., thermally activated aluminosilicate mineralsuch as fly ash, calcium sulfoaluminate cement and calcium sulfate),even more preferably from about 1.25% to about 2.75% by total dry weightof the cementitious reactive materials, and most preferably from about1.5% to about 2.5% by total dry weight of the cementitious reactivematerials.

The dimensionally stable geopolymer compositions of preferredembodiments of the invention further evidence a surprising reduction inthe maximum temperature rise during curing of the composition relativeto prior geopolymer cementitious products. For this and related reasons,these embodiments resist thermal cracking to an unexpected degree. Forexample, in some preferred embodiments, the temperature rise typicallyis less than about 50° F. (28° C.), more preferably less than about 40°F. (22° C.), and most preferably less than about 30° F. (17° C.).

These and other preferred embodiments of the invention also exhibit anunexpected rate of early age strength development. For example, in somesuch embodiments, their 4-hour compressive strength may exceed about1000 psi (6.9 MPa), preferably exceeding about 1500 psi (10.3 MPa), mostpreferably exceeding about 2500 psi (17.2 MPa). In such embodiments,their 24-hour compressive strength development may exceed about 1500 psi(10.3 MPa), more preferably exceeding about 2500 psi (17.2 MPa), andmost preferably exceeding about 3500 psi (24.1 MPa). In those and otherpreferred embodiments, the 28-day compressive strength further mayexceed about 3500 psi (24.1 MPa), more preferably exceeding about 4500psi (31.0 MPa), and most preferably exceeding about 5500 psi (37.9 MPa).In yet other embodiments, the compositions are capable of developingcompressive strength after 1 to 4 hours from about 500 psi (3.5 MPa) toabout 4000 psi (27.6 MPa), more preferably from about 1500 to about 5000psi (10.3 to 34.5 MPa) after 24 hours, and most preferably from about3500 to about 10000 psi (24.1 to 70 MPa) after 28 days.

Furthermore, the geopolymer cementitious compositions of certain of thepreferred embodiments of the invention also have extremely gooddurability under wet conditions, with ultimate wet compressive strengthssimilar to dry compressive strengths. For example, in certainembodiments, their water saturated compressive strength at 28-daystypically may exceed about 3500 psi (24.1 MPa), more preferablyexceeding about 4500 psi (31.0 MPa), and most preferably exceeding about5500 psi (37.9 MPa).

Because the set times from slurry to solid state for alkali metalactivated geopolymers, as well as the combined calcium sulfoaluminatecements and calcium sulfates, typically are relatively short, it wasexpected that the preferred embodiments combining all of thesecomponents also would have short set times and limited working times.Surprisingly, however, the set times provided by the preferredembodiments of the invention are not limited to short set times (oftenless than 15 minutes), but provide significant control over the slurrysetting reactions allowing significant extensions of the slurry set andworking times.

For example, in some embodiments, the composition may be formulated fora short setting time, such as less than about 10 minutes. In otherpreferred embodiments, the composition may be formulated for an extendedsetting of between about 10 to about 30 minutes. In yet other morepreferred embodiments, the composition formulation is preferablyselected to provide a setting time of about 30 to about 60 minutes. Instill other most preferred embodiments, the composition may beformulated for setting times as long as about 60 to about 120 minutes,about 120 to about 240 minutes, or longer times if desired.

The setting times of such embodiments, in addition, can be selected, andif desired extended, without significant (if any) loss in shrinkresistance properties, compressive strength and other strengthproperties. As a result, such embodiments unexpectedly can be used inapplications where prior geopolymer based products and cementitiousproducts with geopolymer components could not be used due to a need forextended set and working times without unacceptable shrinkage orstrength loss.

In certain preferred embodiments, the compositions of the invention alsodevelop exceptional tensile bond strength with an underlying substrate.For example, the preferable tensile bond strength between suchembodiments and a concrete substrate preferably exceeds about 200 psi(1.4 MPa) and most preferably exceeds about 300 psi (2.1 MPa). In someembodiments, the surface pH of the fully cured and hardeneddimensionally stable geopolymer cementitious compositions of theinvention also are improved relative to Portland cement based materialsand products, which typically have a surface pH of greater than 12 andmore typically greater than 13. In certain preferred embodiments, suchcompositions are measured 16 hours after installation and preferablyhave a pH less than about 11, more preferably less than about 10.5, andmost preferably less than about 10. In this context, surface pH ismeasured using the ASTM F-710 (2011) testing standard.

In many preferred embodiments, the geopolymer cementitious compositionsof the invention do not require calcium silicate based hydrauliccements, such as Portland cements, for strength development anddimensional stability. In other embodiments, Portland cements can beincorporated to provide specific desired properties. However, it wassurprisingly found that, depending on the specific composition of theembodiment, an excess amount of Portland cement actually decreased thecomposition's dimensional stability during and after curing, instead ofincreasing its dimensional stability.

For preferred embodiments of the invention incorporating calciumsilicate based hydraulic cements, the limit on such hydraulic cementsmay vary depending on the specific composition of the embodiment, butcan be identified by an increase in shrinkage relative to the shrinkageof the same embodiment with a reduced amount of the calcium silicatehydraulic cement. In certain of such embodiments the Portland cementcontent should not exceed about 15 weight % of the weight of reactivepowder components in another preferred embodiment, it should not exceed10 weight % of the weight of reactive powder components, and in yetanother preferred it should not exceed about 5 weight % of the weight ofreactive powder components and yet another preferred embodiment, thereis no substantial amount of Portland cement in the reactive powdercomponents.

It also has surprisingly been found in some embodiments that an excessamount of calcium sulfoaluminate cement can cause a loss of dimensionalstability, as indicated by an increase in shrinkage after the initialset of the composition. For applications requiring significant degree ofdimensional stability and/or shrinkage control to prevent cracking,delamination and other modes of failure, the amount of calciumsulfoaluminate cement is preferably about 10 to about 40 parts by dryweight relative to 100 parts by dry weight of thermally activatedaluminosilicate mineral.

In other preferred embodiments, it also has been unexpectedly found thatthe amount of calcium sulfate present in proportion to calciumsulfoaluminate cement in the composition can moderate potential adverseeffects, such as shrinkage, caused by the calcium sulfoaluminate cementcontent. In such embodiments, the calcium sulfate amount is preferablyabout 2 to about 200 parts by weight relative to 100 parts by weight ofcalcium sulfoaluminate cement.

For the most effective control of material shrinkage of thoseembodiments, the amount of calcium sulfate is about 10 to about 100parts by dry weight relative to 100 parts by dry weight of calciumsulfoaluminate cement, more preferably about 15 to about 75 parts by dryweight relative to 100 parts by dry weight of calcium sulfoaluminatecement, and most preferably about 20 to about 50 parts by dry weightrelative to 100 parts by dry weight of calcium sulfoaluminate cement. Inembodiments where an increase in early age compressive strength isimportant, it is preferred amount of calcium sulfate amount is about 10to about 50 parts to about 100 parts by dry weight of calciumsulfoaluminate cement.

In yet other embodiments of the invention, the type of calcium sulfate(primarily dihydrate, hemihydrate, or anhydrite) added to thecomposition can have a significant influence on the development of theearly age compressive strength of the partially cured composition (i.e.at less than about 24 hours). Surprisingly, it has been found thatvarious embodiments using primarily calcium sulfate anhydrite have agreater early compressive strength than embodiments using primarily thedihydrate form and, in some embodiments, can have early compressivestrengths comparable to those using primarily calcium sulfatehemihydrate. In other embodiments, two or more of the calcium sulfatetypes (dihydrate, hemihydrate, or anhydrite) can be employed together,and the amounts of the different types adjusted to provide improvedcontrol of the composition's compressive strength. Similarly, thedifferent types and amounts of calcium sulfate can be employed alone orin combination to adjust the desired shrinkage and other properties ofthe composition.

Where shrinkage performance is of central concern, other embodiments ofthe invention incorporate calcium sulfates with average particle sizespreferably from about 1 to about 100 microns, about 1 to about 50microns, and about 1 to about 20 microns. These embodiments provide asurprising improvement in shrinkage resistance, and in otherembodiments, the calcium sulfate particle sizes in at least thepreferred ranges can provide an important contribution to improved ratesof strength development during curing of the compositions.

In yet other embodiments, it was surprisingly found that substantiallywater insoluble anhydrous calcium sulfate (anhydrite) can provideimportant benefits, notwithstanding its low water solubility andpreviously presumed limited, if any, reactivity in the composition. Forexample, it was unexpectedly found that anhydrite provided significantimproved dimensional stability control by reducing the shrinkage duringcuring of those and other embodiments relative to prior artcompositions. Anhydrite also provided significantly improved early andlong term compressive strength relative to prior art compositions, and,in some instances, early and long term compressive strengths comparableto or better than compositions utilizing calcium sulfate hemihydrate ordihydrate as the calcium sulfate source. The selection of the type ofcalcium sulfate used in a particular embodiment will depend on thedesired rate of early age strength development in combination with abalance of other properties, such as set time and shrinkage resistancefor a particular end application.

In other embodiments, the particle size and morphology of calciumsulfate provides a significant and surprising influence on developmentof early age strength (less than about 24 hours) of the compositions. Insuch embodiments, the use of a relatively a small particle size calciumsulfate provides a more rapid development in early age compressivestrength. In those embodiments, the preferred average particle size ofcalcium sulfate ranges from about 1 to 100 microns, more preferably fromabout 1 to 50 microns, and most preferably from about 1 to 20 microns.

In certain embodiments, the compositions also exhibit a self-levelingbehavior after initial mixing while providing one or more of theaforementioned surprising performance characteristics. The self-levelingaspect of material is useful in a variety of situations and applicationssuch as self-leveling underlayments for floors, concrete toppings,manufacturing of precise concrete products and panels, placement ofslurry in heavily reinforced construction elements, etc. Thecompositions of those embodiments are self-leveling after initial mixingwith water to the reactive powder of the invention at a weight ratio ofabout 0.15 to about 0.4, more preferably, 0.17 to 0.35, yet morepreferably 0.20 to 0.30. Alternatively, in other embodiments, thecompositions also can be provided in a shapeable, thick paste likeconsistency after initial mixing while similarly providing one or moreimproved performance characteristics.

A preferable formulation for self-leveling and patching compositionscomprises about 65 to about 95 weight percent fly ash, about 2 to about30 weight percent calcium sulfoaluminate cement, and about 0.2 to about15 weight percent calcium sulfate. In some embodiments, the geopolymericcementitious composition of the invention can be spread on a surface ofa substrate, wherein the geopolymeric cementitious binder is mixed as aself-leveling product and is poured to an effective thickness of about0.02 cm to about 7.5 cm.

The physical characteristics of such products provide good examples ofbenefits of those embodiments, i.e. dimensional stability, resistance todimensional movement and physical distress, and high surface resistanceto abrasion and wear, suitable for use in commercial, industrial, andother high traffic areas. Time consuming and expensive substrate surfacepreparation measures such as shot-blasting, scarifying, water jetting,scabbing or milling can be minimized or avoided altogether, depending onthe application.

In other aspects of the invention, preferred embodiments provide methodsfor making dimensionally stable, cementitious compositions with settingtimes adaptable to specific applications, good early age strengthdevelopment and ultimate compressive and other strength characteristics,improved surface pH, improved tensile bond strength with substrates andother benefits. In certain preferred embodiments, those methods comprisethe steps of preparing a surprisingly effective, synergistic mixture ofthermally activated aluminosilicates, preferably from Class C fly ash,calcium sulfoaluminate cement, a calcium sulfate, and an alkali metalchemical activator.

In certain preferred embodiments of such methods, the preferred mixturesare prepared using components, such as those mentioned above, to form acementitious reactive powder comprising thermally activated Class C flyash, calcium sulfoaluminate cement, and a calcium sulfate selected fromthe group consisting of calcium sulfate dihydrate, calcium sulfatehemihydrate, anhydrous calcium sulfate and mixtures thereof (preferablyin a fine grain form with particle size less than about 300 microns).

In those embodiments, a chemical activator further is added to themixture either in dry or liquid form comprising an alkali metal salt orbase preferably selected from the group consisting of alkali metal saltsof organic acids, alkali metal hydroxides, and alkali metal silicates.In subsequent steps, water is added and optionally a superplasticizer,particularly a carboxylated plasticizer material, to form stable slurrymixtures that can be used in applications suitable for geopolymericcementitious products.

In the preferred methods, the mixtures are prepared at an initialtemperature of about 0° C. to about 50° C., more preferably an initialtemperature of about 5° C. to about 40° C., even more preferably aninitial temperature of about 10° C. to about 35° C., most preferablyambient temperature of about 25° C. In such embodiments, the initialtemperature of the overall mixture is measured during the first minuteafter the cementitious reactive powder; activator and water are firstall present in the mixture. Of course the temperature of the overallmixture can vary during this first minute but in such preferredembodiments; the temperature of the slurry preferably remains within thelisted range.

In some preferred embodiments, the slurry can be mixed using relativelylow energies, while still achieving a well-mixed composition. In some ofsuch preferred methods, the slurry is mixed with energies equivalent tothose provided by low speed hand drill mixers or equivalent mixershaving a rating of about 250 RPM or greater. Accordingly, the geopolymercompositions of such preferred embodiments are easy to mix despite theuse of the relatively small amounts of water used to make the slurryused to form the final composition.

In many embodiments, other additives which are not consideredcementitious reactive powder may be incorporated into the slurry andoverall geopolymeric cementitious composition. Such other additives, forexample, water reducing agents such as the above mentionedsuperplasticizers, set accelerating agents, set retarding agents,air-entraining agents, foaming agents, wetting agents, shrinkage controlagents, viscosity modifying agents (thickeners), film-formingredispersible polymer powders, film-forming polymer dispersions,coloring agents, corrosion control agents, alkali-silica reactionreducing admixtures, discrete reinforcing fibers, and internal curingagents. Other additives may include fillers, such as one or more of sandand/or other aggregates, lightweight fillers, pozzolanic mineral,mineral fillers, etc.

While separately discussed above, each of the preferred geopolymericcompositions and mixtures of the invention has at least one, and canhave a combination of two or more of the above mentioned distinctiveadvantages (as well as those apparent from the further discussion,examples and data herein) relative to prior art geopolymericcementitious compositions.

Many, if not most, of the embodiments of the invention areenvironmentally sustainable, utilizing fly ash geopolymers that comprisepost industrial waste as a primary raw material source. Thissignificantly reduces the life cycle carbon footprint and the life cycleembodied energy of the manufactured product.

The geopolymer cementitious compositions of preferred embodiments of thepresent invention can be used where other cementitious materials areused, particularly applications where setting and working timeflexibility, dimensional stability, compressive strength and/or otherstrength properties are important or necessary. For example, in variousconcrete product applications including structural concrete panels forfloors, slabs, and walls, wall and floor underlayment for installationof floor-finish materials such as ceramic tiles, natural stones, vinyltiles, VCTs and carpet, highway overlays and bridge repair, sidewalksand other slabs-on-ground, exterior stucco and finish plasters,self-leveling topping and capping underlayments, guniting and shotcretefor stabilization of earth and rocks in foundations, mountain slopes andmines, patching repair mortars for filling and smoothing cracks, holesand other uneven surfaces, statuary and murals for interior and exteriorapplications, as well as patching materials for repairing pot holes inroads and bridge decks.

Other examples include uses for precast concrete articles, as well asbuilding products such as cementitious boards, masonry blocks, bricks,and pavers with excellent moisture durability. In some applications,such precast concrete products such as cement boards are preferably madeunder conditions which provide setting times appropriate for pouringinto a stationary or moving form or over a continuously moving belt.

The geopolymer compositions of some embodiments of the invention can beused with different fillers and additives including foaming agents andair entraining agents for adding air in specific proportions to makelightweight cementitious products, including precast constructionelements, construction repair products, and patching compositions whichhave good expansion properties and no shrinkage e.g. suitable for roadrepairs and pavements.

Other advantages, benefits and aspects of various embodiment of theinvention are discussed below, are illustrated in the accompanyingfigures, and will be understood by those of skill in the art from themore detailed disclosure below. All percentages, ratios and proportionsherein are by weight, unless otherwise specified.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A—is a graph of time of shrinkage results of Comparative Example 1

FIG. 1B is a photograph of slump of Example 1.

FIG. 2 is a photograph of slump of Comparative Example 2.

FIG. 3A is a photograph of slump of Comparative Example 3.

FIG. 3B is a graph of time of shrinkage results of Comparative Example 3

FIG. 4A is a photograph of initial flow behavior and slump ofcompositions in Example 4 for Mixes 1 and 2.

FIG. 4B is a photograph of initial flow behavior and slump ofcompositions in Example 4 for Mix 3.

FIG. 4C is a photograph of initial flow behavior and slump ofcompositions in Example 4 for Mix 4.

FIG. 4D is a photograph of compositions investigated in Example 4—Allbars for mixes 1, 2-1 and 2-2, 3-1 and 3-2 and 4-1 and 4-2 (left toright) cracked in the mold.

FIG. 5A is a photograph of slump patties of Mixes 1-2 (left to right)and 3-4 (left to right) of Example 5.

FIG. 5B is a bar graph of initial flow and slump results of Example 5.

FIG. 5C is a graph of slurry temperature rise results of Example 5.

FIG. 6A is a graph of time of shrinkage of Example 6.

FIG. 6B is a graph of slurry temperature rise of composition of theinvention in Example 6.

FIG. 7A is a photograph of slump patties of Mix 1 of the compositions ofExample 7.

FIG. 7B is a photograph of slump patties of Mixes 2, 3 and 4 thecompositions of Example 7.

FIG. 7C is a graph of shrinkage of compositions of the invention inExample 7.

FIG. 7D is a graph of slurry temperature rise of compositions of theinvention of Example 7.

FIG. 8A is a graph of shrinkage of compositions of the invention inExample 8.

FIG. 8B is a graph of slurry temperature rise of compositions of theinvention of Example 8.

FIG. 9A is a graph of shrinkage of compositions of the invention inExample 9.

FIG. 9B is a graph of slurry temperature rise of compositions of theinvention results of Example 9.

FIG. 10A is a graph of shrinkage of compositions of the invention inExample 10.

FIG. 10 B is a graph of slurry temperature rise of compositions of theinvention results of Example 10.

FIG. 11A shows photographs of slump patties of compositions of Example11.

FIG. 11B is a graph of shrinkage of compositions of the invention inExample 11.

FIG. 11C is a graph of slurry temperature rise of compositions of theinvention of Example 11.

FIG. 12A is a graph of shrinkage of compositions of the invention inExample 12.

FIG. 12B is a graph of slurry temperature rise of compositions of theinvention results of Example 12.

FIG. 13A is a photograph of slump patties of compositions of theinvention of Example 13.

FIG. 13B is a graph of shrinkage of compositions of the invention inExample 13.

FIG. 13C is a graph of slurry temperature rise of compositions of theinvention of Example 13.

FIG. 14 is a graph of shrinkage of compositions of the invention inExample 14.

FIG. 15A is a graph of shrinkage of compositions of the invention inExample 15.

FIG. 15B is a graph of slurry temperature rise of compositions of theinvention of Example 15.

FIG. 16A contains photographs of slump patties of compositions of theinvention of Example 16.

FIG. 16B is a graph of shrinkage of compositions of the invention inExample 16.

FIG. 17A contains photographs of slump patties of compositions of theinvention of Example 17.

FIG. 17B is a graph of shrinkage of compositions of the invention inExample 17.

FIG. 17C is a graph of slurry temperature rise of compositions of theinvention of Example 17.

FIG. 18A is a graph of shrinkage of compositions of the invention inExample 18.

FIG. 18B is a graph of slurry temperature rise of compositions of theinvention of Example 18.

FIG. 19A is a graph of shrinkage of compositions of the invention inExample 13.

FIG. 19B is a graph of slurry temperature rise of compositions of theinvention of Example 19.

FIG. 20A is a graph of shrinkage of compositions of the invention inExample 20.

FIG. 20B is a graph of slurry temperature rise of compositions of theinvention of Example 20.

FIG. 21A is a graph of shrinkage of compositions of the invention inExample 21.

FIG. 21B is a photograph of 4-hour shrinkage bars for Mix 1 of Example21.

FIG. 21C is a graph of the very early age material shrinkage ofcompositions of the invention of Example 21 (Shrinkage testing initiatedat the age of 1-hour).

FIG. 21D is a graph of slurry temperature rise of compositions ofinvention of Example 21.

FIG. 22A is a graph of shrinkage of compositions of the invention inExample 22.

FIG. 22B is a graph of slurry temperature rise of compositions of theinvention of Example 22.

FIG. 23 is a graph of very early age shrinkage of compositions of theinvention of Example 23 (Shrinkage testing initiated at the age of1-hour).

FIG. 24 is a graph of shrinkage of compositions of invention in Example27.

FIG. 25 comprises photographs of the cast cubes (in the brass cubemolds) of compositions investigated in Example 28.

FIG. 26 is a graph of shrinkage of compositions of invention in Example29.

FIG. 27A is a graph of shrinkage of compositions of the invention inExample 30.

FIG. 27B is a graph of the exothermic and slurry temperature risebehavior of composition of the in Example 30.

FIG. 28 is a graph of the exothermic and slurry temperature risebehavior of the lightweight compositions of some embodiments of theinvention in Example 31.

DETAILED DESCRIPTION OF THE INVENTION

TABLE A shows the composition of the dimensionally stable geopolymercementitious composition of some preferred embodiments of the inventionexpressed in parts by weight (pbw) of individual or aggregatedcomponents.

TABLE A shows the dimensionally stable geopolymer cementitiouscompositions of such preferred embodiments of the invention arecomprised of two components—Reactive Powder Component A (also known as“Cementitious Reactive Material” and which for purposes of thisinvention is defined as a thermally activated aluminosilicate, calciumsulfoaluminate cement, a calcium sulfate, and any additional reactivecement to the extent it is added to the other listed ingredients) andActivator Component B. Reactive Powder Component A is blend of materialscomprising thermally activated aluminosilicate mineral comprising ClassC fly ash, calcium sulfoaluminate cement, and calcium sulfate. ActivatorComponent B comprises an alkali metal chemical activator or mixturesthereof, which can be a powder or aqueous solution. Reactive PowderComponent A and Activator Component B combined together form thereactive mixture of the geopolymer cementitious compositions of suchpreferred embodiments of the invention.

TABLE A Reactive geopolymer cementitious compositions of some preferredembodiments of the invention. More Broad Preferred Preferred ReactivePowder Component A: Thermally activated aluminosilicate 100 100 100mineral comprising Class C Fly ash, pbw Calcium sulfoaluminate cement,1-100 2.5-50  5-30 pbw per 100 pbw of thermally activatedaluminosilicate mineral Calcium sulfate, pbw per 100 2-100   5-75 10-50pbw of calcium sulfoaluminate cement. Activator Component B: 1 to 1.25to 1.5 to Alkali metal chemical activator, 6% 4% 2.5% weight % basedupon the total weight of Component A (i.e., aluminosilicate calciumsulfoaluminate cement, and calcium sulfate).

TABLE B represents full density (preferable densities in the range of100 to 160 pounds per cubic foot) formulations of preferred embodimentsincorporating the binder of TABLE A and other ingredients.

TABLE B TABLE B—Ingredient Amounts More pre- Ingredient Broad Preferredferred Reactive Powder Component A: Thermally activated aluminosilicate100 100 100 mineral comprising Class C Fly ash, pbw Calciumsulfoaluminate cement, pbw 2-100 2.5-50   5-30 per 100 pbw of thermallyactivated aluminosilicate mineral Calcium sulfate, pbw per 100 pbw of2-100  5-75 10-50 calcium sulfoaluminate cement Activator Component B: 1to 1.25 to 1.5 to Alkali metal chemical activator, 6% 4% 2.5% weight %based upon the total weight of Component A Superplasticizer/ReactivePowder 0 to 0.25- 0.5- Component A (weight %) 4.0% 2.5% 1.5%Sand/Reactive Powder Component 0-4    0.50-3 0.75- A Ratio (by weight)1.5 Inorganic Mineral Filler/Reactive 0-2      0-1 0-0.5 PowderComponent A Ratio (by weight) Defoaming Agent/Reactive Powder 0-1% 0- 0-Component A (weight %) 0.75% 0.50% Organic Rheology Control   0-0.5% 0-0- Agent/Reactive Powder Component 0.25% 0.15% A (weight %) InorganicRheology Control 0-3% 0-2% 0-1% Agent/Reactive Powder Compo- nent A(weight %) Coloring Pigments/Reactive Powder 0-5% 0- 0-1% Component A(weight %) 2.5% Efflorescence Suppression 0-3% 0-2% 0-1% Agent/ReactivePowder Component A (weight %) Film Forming Redispersible Polymer  0-20% 0-10% 0-5% Powder/Reactive Powder Component A (weight %) Film FormingPolymer Dispersion/  0-40%  0-20%  0-10% Reactive Powder Component A(weight %) Water/Reactive Powder Component 0.17- 0.20- 0.22- A Ratio (byweight) 0.40 0.35 0.30

TABLE C represents lightweight density (preferable densities in therange of 10 to 125 pounds per cubic foot) of preferred formulationsincorporating the binder of TABLE A and other ingredients.

TABLE C TABLE C—Ingredient Amounts More Ingredient Broad Preferredpreferred Reactive Powder Component A: Thermally activatedaluminosilicate 100 100 100 mineral comprising Class C Fly ash, pbwCalcium sulfoaluminate cement, pbw 2-100 2.5-50   5-30 per 100 pbw ofthermally activated aluminosilicate mineral Calcium sulfate, pbw per 100pbw 2-100  5-75 10-50 of calcium sulfoaluminate cement. ActivatorComponent B: 1 to 1.25 to 1.5 to Alkali metal chemical activator 6% 4%2.5% weight % based upon the total weight of Component ASuperplasticizer/Reactive Powder 0 to 0.25- 0.50- Component A (weight %)4.0% 2.5% 1.5% Sand/Reactive Powder Component A 0-4    0-2 0-1.0 Ratio(by weight) Inorganic Mineral Filler/Reactive 0-2    0-1 0-0.5 PowderComponent A Ratio (by weight) Defoaming Agent/Reactive Powder 0-1% 0- 0-Component A (weight %) 0.75% 0.50% Organic Rheology Control 0- 0- 0-Agent/Reactive Powder Component A 0.50% 0.25% 0.15% (weight %) InorganicRheology Control 0-3% 0-2% 0-1% Agent/Reactive Powder Component A(weight %) Coloring Pigments/Reactive Powder 0-5% 0- 0-1% Component A(weight %) 2.5% Efflorescence Suppression 0-3% 0-2% 0-1% Agent/ReactivePowder Component A (weight %) Film Forming Redispersible Polymer  0-20% 0-10% 0-5% Powder/Reactive Powder Component A (weight %) Film FormingPolymer  0-40%  0-20%  0-10% Dispersion/Reactive Powder Component A(weight %) Lightweight Filler/Reactive Powder 0-2    0.01-1 0.02-Component A Ratio (by weight) 0.75 Water/Reactive Powder Component A0.17- 0.20- 0.22- Ratio (by weight) 0.40 0.35 0.30

TABLE D represents lightweight or full density (preferable densities inthe range of 40 to 160 pounds per cubic foot) of certain preferredformulations incorporating the binder of TABLE A, coarse aggregate andother ingredients.

TABLE D TABLE D—Ingredient Amounts More Ingredient Broad Preferredpreferred Reactive Powder Component A: Thermally activatedaluminosilicate 100 100 100 mineral comprising Class C Fly ash, pbwCalcium sulfoaluminate cement, pbw  2-100 2.5-50   5-30 per 100 pbwthermally activated aluminosilicate mineral Calcium sulfate, pbw per 100pbw of  2-100  5-75 10-50 Calcium sulfoaluminate cement. ActivatorComponent B: 1 to 1.25 to 1.5 to Alkali metal chemical activator, weight6% 4% 2.5% based upon the total weight of Component ASuperplasticizer/Reactive Powder 0 to 0.25- 0.50- Component A (weight %)4.0% 2.5% 1.5% Sand/Reactive Powder Component A 0-4 0.50-3   1-2 Ratio(by weight) Inorganic Mineral Filler/Reactive 0-2 0-1   0-0.5 PowderComponent A Ratio (by weight) Defoaming Agent/Reactive Powder 0-1% 0- 0-Component A (weight %) 0.75% 0.50% Organic Rheology Control 0- 0- 0-Agent/Reactive Powder Component A 0.50% 0.25% 0.15% (weight %) InorganicRheology Control 0-3% 0-2% 0-1% Agent/Reactive Powder Component A(weight %) Coloring Pigments/Reactive Powder 0-5% 0- 0-1% Component A(weight %) 2.5% Efflorescence Suppression 0-3% 0-2% 0-1% Agent/ReactivePowder Component A (weight %) Film Forming Redispersible Polymer  0-20% 0-10% 0-5% Powder/Reactive Powder Component A (weight %) Film FormingPolymer  0-40%  0-20%  0-10% Dispersion/Reactive Powder Component A(weight %) Coarse Aggregate/Reactive Powder 0.5-5   0.5-4   1-3Component A Ratio (by weight) Lightweight Filler/Reactive Powder 0-2 0-1  0-0.50 Component A Ratio (by weight) Water/Reactive Powder ofComponent 0.20- 0.22- 0.25- A parts by weight water to pbw 0.40 0.350.30 Component A

The long-term free shrinkage of the geopolymer cementitious bindermixtures of some embodiments of the invention with shrinkagemeasurements initiated between about 1 to about 4 hours after mixing toform an aqueous mixture is about 0.3% or less, preferably less thanabout 0.2%, and more preferably less than about 0.1%, and mostpreferably less than about 0.05%. As mentioned previously, thesynergistic interaction between the thermally activated aluminosilicatemineral, calcium sulfoaluminate cement, appropriately selected sourceand amount of calcium sulfate, and appropriately selected alkali metalactivator used at appropriate amount according to some embodiments ofthis invention helps to minimize the material shrinkage.

The geopolymer reaction of aluminosilicate mineral such as fly ash withan alkali metal activator such as alkali metal citrate is known toinvolve an extremely rapid rate of reaction in which significant amountof heat is released due to the exothermic reaction involved. This rapidrate of exothermic reaction leads to the formation of aluminosilicatecompounds and the material gels-up and hardens extremely quickly (in amatter of minutes). Similarly, interaction of calcium sulfoaluminatecement with calcium sulfate also is known to involve an extremely rapidrate of reaction in which significant amount of heat is released due tothe exothermic reaction. As a result of this rapid exothermic reaction,hydration products of calcium sulfoaluminate compound are formed and thematerial gels-up and hardens extremely quickly, again in a matter ofminutes. An extremely short setting time is problematic in someapplications since it provides a short working life (pot life) thatcauses significant difficulties with processing and placement of rapidsetting material in actual field applications. Also, the large amount ofheat generated by the rapid exothermic reactions can lead to undesirablethermal expansion and consequent cracking and disruption of material.

Those skilled in the art would expect that if the aforementioned tworapid setting exothermic reactions (that is, the reaction ofaluminosilicate mineral such as fly ash with an alkali metal salt andthe reaction of calcium sulfoaluminate cement with calcium sulfate) wereallowed to occur concurrently as a result of mixing aluminosilicatemineral, alkali metal activator, calcium sulfoaluminate cement andcalcium sulfate together, the resulting material would undesirablyrelease even more heat and would undesirably gel-up and harden much morerapidly in comparison with the scenarios where the above two reactionswere allowed to occur independently and wherein the high heat generationand rapid set are already at undesirable levels. In embodiments of thepresent invention employing all four reactive components noted above, itwas surprisingly found that such is not the case. When thealuminosilicate mineral, alkali metal activator, calcium sulfoaluminatecement and calcium sulfate are mixed together, the resulting material isless exothermic and has extended gelation and hardening times comparedwith both of the known two-component reactive systems described above.There appears to be a synergistic interaction occurring between thesefour raw materials that provides the surprising results in someembodiments of the invention.

Yet another very surprising result found in some embodiments of thisinvention is the observed significant reduction in material shrinkagewhen the aluminosilicate mineral and alkali metal activator are reactedtogether with the calcium sulfoaluminate cement and calcium sulfate.See, for example, the comparisons in the Examples below of inventivefour-reactive-component systems of the invention with the non-inventivesystems of Comparative Examples 1-4 containing only two or three of thereactive components. Significant reductions in material shrinkage occureven when relatively small amounts of calcium sulfoaluminate cement andcalcium sulfate are included in the reactive mixture with thealuminosilicate mineral and activator.

It has been very surprisingly found that the amount of calciumsulfoaluminate cement in the geopolymer cementitious binder compositionsof some embodiments of the present invention affects the degree ofmaterial shrinkage measured after the initial setting of the material.It has also been surprisingly been found that beyond some amount ofcalcium sulfoaluminate cement in a given embodiment the amount ofmaterial shrinkage occurring after the initial set of the materialbegins to increase.

TABLE D1 shows ingredient amounts for some preferred embodimentsreflecting the ability to control shrinkage of the compositions afterthe initial set.

TABLE D1 TABLE D1 More Ingredient Broad Preferred preferred In generalthe amount of calcium 1-200 2.5 to 100 5 to 50 sulfoaluminate cement per100 parts by parts by parts by parts by weight thermally activatedweight weight weight aluminosilicate mineral. For most effective controlon material 2.5 to 75 3.5 to 50 5 to 30 shrinkage, the amount of calciumparts by parts by parts by sulfoaluminate cement per 100 parts weightweight weight by weight thermally activated aluminosilicate mineral. Forapplications requiring very high 5 to 40 5 to 35 5 to 30 degree ofshrinkage control to prevent parts by parts by parts by cracking,delamination and other weight weight weight modes of failure, the amountof cal- cium sulfoaluminate cement per 100 parts by weight thermallyactivated aluminosilicate mineral.

It has also been unexpectedly found the amount of calcium sulfatepresent in the mixture has a significant influence on the degree ofmaterial shrinkage of geopolymer cementitious compositions of someembodiments of the invention.

TABLE D2 shows ingredient amounts in some embodiments of the invention,of the amount of calcium sulfate per 100 parts calcium sulfoaluminatecement that can be used to control material shrinkage.

TABLE D2 TABLE D2 More Ingredient Broad Preferred preferred In generalthe amount of calcium 2 to 200 10 to 100 20 to 75 sulfate per 100 partsby weight calcium parts by parts by parts by sulfoaluminate cement.weight weight weight For most effective control on material 2 to 100 5to 75 10 to 50 shrinkage of the geopolymer cementi- parts by parts byparts by tious binder compositions of some weight weight weightembodiments of the invention, the amount of calcium sulfate per 100parts calcium sulfoaluminate cement.

For a given amount of alkali metal activator and other components in thecomposition of some embodiments of the invention, usage of calciumsulfate dihydrate has been found to provide the most effective controlin minimizing the material shrinkage. Usage of anhydrous calcium sulfate(anhydrite) and calcium sulfate hemihydrate also provide excellentcontrol in lowering the material shrinkage of the geopolymercementitious binder compositions of some embodiments of the invention.Calcium sulfate dihydrate and anhydrous calcium sulfate (anhydrite) arethe preferred form of calcium sulfate of this invention. Morepreferably, the calcium sulfate is provided in fine particle size.

It has been surprisingly found the amount of alkali metal activator hasa significant influence on the degree of material shrinkage ofgeopolymer cementitious binder compositions of some embodiments of theinvention. TABLE D3 shows ingredient amounts for the % amount of alkalimetal activator relative to the weight of the cementitious materials(i.e. thermally activated aluminosilicate mineral, calciumsulfoaluminate cement, and calcium sulfate) preferred to achieve thisbenefit.

TABLE D3 TABLE D3 More Ingredient Broad Preferred preferred For the mosteffective control 1 to 6% by 1.25% to 4% 1.5% to on shrinkage of thegeopolymer weight of the by weight of 2.5% by cementitious bindercomposi- cementitious the cementi- weight of tions of some embodimentsof materials tious mate- the cemen- the invention, the weight % of rialstitious ma- alkali metal activator based upon terials the total weightof the cementi- tious materials (i.e., thermally activatedaluminosilicate mineral, calcium sulfoaluminate cement, and calciumsulfate).

It has surprisingly been found that incorporation of calcium silicatebased hydraulic cements such as Portland cement in the geopolymercompositions of some embodiments of the invention has a negativeinfluence on the dimensional stability of the resulting material.Increase in Portland cement amount added to the geopolymer compositionsof such embodiments increases the shrinkage of the resultingcompositions. Increase in material shrinkage in the presence of Portlandcement results even when calcium sulfoaluminate cement, calcium sulfateand alkali metal chemical activator are present in such embodiments. Forexample, it has been found incorporation of 15%, 33%, 52%, and 74%Portland cement on a dry basis, based upon the total weight of the solidcementitious material (as used herein, “cementitious materials” includethe dry components of the mixture including the thermally activatedaluminosilicate mineral, all cement materials, and calcium sulfate inthe reactive powder compositions of some embodiments increased the8-week material free shrinkage, measured after the material initial set,to about 0.15%, 0.23%, 0.31%, and 0.48%, respectively.

Thus, in embodiments where shrinkage in the above amounts is a concern,it is believed, without being bound by theory, that addition of Portlandcement negatively influences the synergistic interaction between thebasic four reactive powders (thermally activated aluminosilicate mineralcalcium sulfoaluminate cement, calcium sulfate and alkali metal chemicalactivator). Hence, the geopolymer cementitious compositions ofembodiments where the above amount of shrinkage is a concern preferablydo not incorporate sufficient Portland cement to produce such undesireddegree of shrinkage.

To form the binder composition, the Reactive Powder Component A(thermally activated aluminosilicate mineral, calcium sulfoaluminatecement, and calcium sulfate), Activator Component B (alkali metalchemical activator), and water are mixed to form a cementitious slurryat an initial temperature (temperature during the first minute theingredients are first all present in the mixture) of about 0° C. toabout 50° C., and preferably about 10 to about 35° C. As a result,geopolymerization reaction ensues, leading to formation ofalumino-silicate geopolymer reaction species and setting and hardeningof the resulting material. Simultaneously, hydration reactions ofcalcium sulfoaluminate and calcium silicate phases also occur leading tosetting and hardening of the resulting material.

The dimensionally stable geopolymer compositions of some preferredembodiments of the invention have extremely low water demand to achievea workable mixture in the fresh state and to produce a strong anddurable material in the hardened state.

The preferable water/total solids weight ratio of the dimensionallystable geopolymer cementitious binders of some embodiments of theinvention in the absence of coarse aggregate is about 0.04 to about0.25, preferably about 0.04 to about 0.20, more preferably about 0.05 toabout 0.175 and most preferably about 0.05 to about 0.15. The preferablewater/total solids ratio of the dimensionally stable geopolymer bindersof some embodiments of the invention in the presence of coarse aggregateis preferably less than about 0.125, more preferably less than about0.10 and most preferably less than about 0.075. Total solids includecementitious materials, aggregate (such as sand or other aggregate),fillers and other solid additives on a water free basis.

A minimum amount of water is provided to accomplish the chemicalhydration and alumino-silicate geopolymerization reactions in suchembodiments. Preferably, in the slurry, the weight ratio of the water topowder cementitious materials about 0.17 to about 0.40, more preferablyabout 0.2 to about 0.35, even more preferably about 0.22 to 0.3. As usedherein, “cementitious materials” is defined as the thermally activatedaluminosilicate mineral, calcium sulfoaluminate cement, and calciumsulfate and any additional cement which may be added to the reactivemixture. The amount of water depends on the needs of the individualmaterials present in the cementitious composition.

Setting of the composition of such embodiments is characterized byinitial and final set times, as measured using Gilmore needles specifiedin the ASTM C266 test procedure. The final set time also corresponds tothe time when a concrete product, e.g., a concrete panel, hassufficiently hardened so that it can be handled.

In general, geopolymeric reactions of thermally activatedaluminosilicate mineral such as fly ash are exothermic. It has beenagain unexpectedly found in some embodiments that fly ash, calciumsulfoaluminate cement, calcium sulfate, and alkali metal chemicalactivator synergistically interact with each other as part of thegeopolymerization reaction to significantly reduce the rate and amountof heat released by the material undergoing exothermic reaction.Appropriate selection of the type of calcium sulfate and its amount, theamount of calcium sulfoaluminate cement, and appropriate selection ofalkali metal chemical activator and its amount are effective in reducingand minimizing the rate and amount of heat released due to the ensuingexothermic reaction.

In general, geopolymeric reaction of thermally activated aluminosilicatemineral such as fly ash also proceeds at a rapid rate and leads to rapidgelation and setting of the material. Typically, when fly ash alone isreacted with an alkali metal chemical activator in accordance with theprior art, the gelation of the material starts within 2 to 3 minutes andthe final set is reached in less than 10 minutes after the formation ofan aqueous mixture.

In preferred embodiments of the invention, it has unexpectedly beenfound that thermally activated aluminosilicate mineral such as fly ash,calcium sulfoaluminate cement, calcium sulfate, and alkali metalchemical activator interact synergistically with each other as part ofthe geopolymerization reaction to significantly increase the gelationtime and final setting time of the resulting material. Appropriateselection of the type of calcium sulfate and its amount, the amount ofcalcium sulfoaluminate cement, and appropriate selection of alkali metalchemical activator and its amount prolong the gelation rate and periodand the final setting time of the resulting material.

For a given amount of alkali metal activator in such embodiments,increase in the calcium sulfate amount has been found to increase thegelation and final setting times of the resulting geopolymercementitious binder compositions. Additionally, for a given amount ofalkali metal activator in such embodiments, increase in the particlesize of calcium sulfate has been found to increase the gelation andfinal setting times of the resulting geopolymer cementitious bindercompositions. Furthermore, amongst different types of calcium sulfate incompositions of the invention, it has been found that calcium sulfatehemihydrate provides the highest increase in the gelation and finalsetting times of the resulting geopolymer cementitious compositions. Forthe geopolymer cementitious binders of some preferred embodiments, thegelation period is about 20 to about 60 minutes, with final settingtimes of about 30 to about 120 minutes. The gelation and final settingtimes are useful in practical field applications as they provide longeropen and working times for the geopolymer cementitious binders of suchembodiments.

As used herein, early age strength of the composition is characterizedby measuring the compressive strength after 3 to 5 hours of curing. Inmany applications, relatively higher early age compressive strength canbe an advantage for a cementitious material because it can withstandhigher stresses without excessive deformation. Achieving high earlystrength also increases the factor of safety relating to handling anduse of manufactured products. Further, due to the achievement of highearly strength, many materials and structures can be opened to trafficand allowed to support non-structural and structural loads at an earlyage. Typically, chemical reactions providing strength development insuch compositions will continue for extended periods after the finalsetting time has been reached.

The geopolymer cementitious binders of some embodiments of the inventionare capable of developing extremely high early age and ultimatecompressive strength. For example, the geopolymer cementitious bindersof some such embodiments are capable of developing compressive strengthafter 1 to 4 hours of about 500 psi to about 4000 psi, about 1500 toabout 5000 psi after 24 hours, and about 3,500 to about 10000 psi after28 days.

In such embodiments, a dramatic increase in early age compressivestrength results when the calcium sulfate amount is about 10% to about50% by weight of calcium sulfoaluminate cement. The type of calciumsulfate has also been surprisingly found to have a significant influenceon the development of early age compressive strength 24 hour) of thegeopolymer cementitious compositions of some embodiments of theinvention. It has been found that the highest increase in early agecompressive strength results when anhydrous calcium sulfate (anhydrite)is employed.

In some embodiments, it has been found that a smaller particle size ofcalcium sulfate leads to a more rapid development in early age 24 hour)strength. When it is desirable to have an extremely rapid rate ofstrength development, the preferred average particle size of calciumsulfate ranges from about 1 to about 30 microns, more preferably fromabout 1 to about 20 microns, and most preferably from about 1 to about10 microns.

Cementitious Reactive Mixture

The cementitious reactive mixture of some preferred embodiments of thepresent invention comprises Reactive Powder Component A and ActivatorComponent B with preferable ranges as shown in TABLE A. The ReactivePowder Component A comprises thermally activated aluminosilicatemineral, calcium sulfoaluminate cement, and calcium sulfate. TheActivator Component B comprises alkali metal chemical activator.

Preferably, the cementitious reactive mixture contains about 10 to about40 wt. % lime. However, this lime does not have to be separately addedlime. Rather it is sometimes included as a chemical component of thethermally activated aluminosilicate mineral.

In addition to the thermally activated aluminosilicate mineral, calciumsulfoaluminate cement, and calcium sulfate, the cementitious reactivepowder may include about 0 to about 5 wt. % of optional cementitiousadditives such as Portland cement. However, preferably there is anabsence of Portland cement as its incorporation increases the materialshrinkage making the material less dimensionally stable.

Class C Fly Ash and Other Thermally Activated Aluminosilicate Mineral

The thermally activated aluminosilicate minerals are in some embodimentsselected from a group consisting of fly ash, blast furnace slag,thermally activated clays, shales, metakaolin, zeolites, marl red mud,ground rock, and ground clay bricks. Preferably, they have Al₂O₃ contentgreater than about 5% by weight. Typically clay or marl is used afterthermal activation by heat treatment at temperatures of from about 600°to about 850° C. The preferred thermally activated aluminosilicateminerals of such embodiments of the invention have high lime (CaO)content in the composition, preferably greater than about 10 wt %, morepreferably greater than about 15%, and most preferably greater thanabout 20%. The most preferred thermally activated alumino-silicatemineral is Class C fly ash, for example, fly ash procured fromcoal-fired power plants. The fly ash also possesses pozzolanicproperties.

ASTM C618 (2008) defines pozzolanic materials as “siliceous or siliceousand aluminous materials which in themselves possess little or nocementitious value, but will, in finely divided form and in the presenceof moisture, chemically react with calcium hydroxide at ordinarytemperatures to form compounds possessing cementitious properties.”

Fly ash is the preferred thermally activated alumino-silicate mineral inthe cementitious reactive powder blend of some embodiments of theinvention. Fly ashes containing high calcium oxide and calcium aluminatecontent (such as Class C fly ashes of ASTM C618 (2008) standard arepreferred as explained below.

Fly ash is a fine powder byproduct formed from the combustion of coal.Electric power plant utility boilers burning pulverized coal producemost commercially available fly ashes. These fly ashes consist mainly ofglassy spherical particles as well as residues of hematite andmagnetite, char, and some crystalline phases formed during cooling. Thestructure, composition and properties of fly ash particles depend uponthe structure and composition of the coal and the combustion processesby which fly ash is formed. ASTM C618 (2008) standard recognizes twomajor classes of fly ashes for use in concrete—Class C and Class F.These two classes of fly ashes are generally derived from differentkinds of coals that are a result of differences in the coal formationprocesses occurring over geological time periods. Class F fly ash isnormally produced from burning anthracite or bituminous coal, whereasClass C fly ash is normally produced from lignite or sub-bituminouscoal.

The ASTM C618 (2008) standard differentiates Class F and Class C flyashes primarily according to their pozzolanic properties. Accordingly,in the ASTM C618 (2008) standard, the major specification differencebetween the Class F fly ash and Class C fly ash is the minimum limit ofSiO₂+Al₂O₃+Fe₂O₃ in the composition. The minimum limit ofSiO₂+Al₂O₃+Fe₂O₃ for Class F fly ash is 70% and for Class C fly ash is50%. Thus, Class F fly ashes are more pozzolanic than the Class C flyashes. Although not explicitly recognized in the ASTM C618 (2008)standard, Class C fly ashes preferably have high calcium oxide (lime)content.

Class C fly ash usually has cementitious properties in addition topozzolanic properties due to free lime (calcium oxide). Class F israrely cementitious when mixed with water alone. Presence of highcalcium oxide content provides Class C fly ashes with cementitiousproperties leading to the formation of calcium silicate and calciumaluminate hydrates when mixed with water. As will be seen in theexamples below, Class C fly ash has been found to provide superiorresults in preferred embodiments of the invention.

In such embodiments, the thermally activated aluminosilicate mineralcomprises Class C fly ash, preferably about 50 to about 100 parts ClassC fly ash per 100 parts by weight thermally activated aluminosilicatemineral, more preferably the thermally activated aluminosilicate mineralcomprises about 75 parts to about 100 parts Class C fly ash per 100parts thermally activated aluminosilicate mineral.

Other types of fly ash, such as Class F fly ash, may also be employed inthose or other preferred embodiments. Preferably, at least about 50 wt.% of the thermally activated aluminosilicate mineral in the cementitiousreactive powder is Class C fly ash with the remainder Class F fly ash orany other thermally activated aluminosilicate mineral. More preferably,about 55 to about 75 wt. % of the thermally activated aluminosilicatemineral in the cementitious reactive powder is Class C fly ash with theremainder Class F or any other thermally activated aluminosilicatemineral. Preferably the thermally activated aluminosilicate mineral isabout 90 to about 100% Class C fly ash, for example 100% Class C Flyash.

The average particle size of the thermally activated alumino-silicateminerals of some embodiments of the present invention is preferably lessthan about 100 microns, more preferably less than about 50 microns, evenmore preferably less than about 25 microns, and most preferably lessthan about 15 microns.

Preferably the binder mixture of the present invention has at most about5 parts metakaolin per 100 parts thermally activated aluminosilicatemineral. More preferably, the binder of the present invention does notinclude significant amounts of meta kaolin. The presence of meta kaolinhas been found to increase the water demand of some mixtures hence itsuse is not desirable in the geopolymer binder compositions of somepreferred embodiments of the invention.

Minerals often found in fly ash are quartz (SiO₂), mullite (Al₂Si₂O₁₃),gehlenite (Ca₂Al₂SiO₇), haematite (Fe₂O₃), magnetite (Fe₃O₄), amongothers. In addition, aluminum silicate polymorphs minerals commonlyfound in rocks such as sillimanite, kyanite and andalusite, all threerepresented by molecular formula of Al₂SiO₅, also are often found in flyash.

Fly ash can also include calcium sulfate or another source of sulfateions which will be in the mixture composition of some embodiments of theinvention.

In some preferred embodiments, the fineness of the fly ash is preferablysuch that less than about 34% is retained on a 325 mesh sieve (U.S.Series) as tested on ASTM Test Procedure C-311 (2011) (“Sampling andTesting Procedures for Fly Ash as Mineral Admixture for Portland CementConcrete”). The average particle size of the fly ash materials useful insuch embodiments is preferably less than about 50 microns, morepreferably less than about 35 microns, even more preferably less thanabout 25 microns, and most preferably less that about 15 microns. Thisfly ash is preferably recovered and used dry because of its self-settingnature.

Class C fly ash made from sub-bituminous coal has the followingrepresentative composition listed in TABLE E. This fly ash is preferablyrecovered and used dry because of its self-setting nature.

TABLE E TABLE E—An example of suitable Class C fly ash ComponentProportion (wt. %) SiO₂ 20-45 Al₂O₂ 10-30 Fe₂O₃  3-15 MgO 0.5-8   SO₃0.5-5   CaO 15-60 K₂O 0.1-4   Na₂O 0.5-6   Loss on Ignition 0-5

A preferable suitable Class F fly ash has the following compositionlisted in TABLE F.

TABLE F TABLE F—Preferable suitable Class F fly ash Component Proportion(wt. %) SiO₂ 50-70 Al₂O₂ 10-40 Fe₂O₃  1-10 MgO 0.5-3   SO₃ 0-4 CaO  0-10K₂O 0.1-4   Na₂O 0.1-6   Loss on Ignition 0-5

Hydraulic Cements

Hydraulic cements for purposes of this invention is a cement thatundergoes a chemical setting reaction when it comes in contact withwater (hydration) and which will not only set (cure) under water butalso forms a water-resistant product.

Hydraulic cements include, but are not limited to, aluminum silicatecements like Portland Cement, calcium sulfoaluminate cement, calciumaluminate based cement and calcium fluoroaluminate cements.

Calcium Sulfoaluminate (CSA) Cements

Calcium sulfoaluminate cement forms an ingredient of the geopolymerbinder compositions of some embodiments of the present invention.Calcium sulfoaluminate (CSA) cements are a different class of cementsfrom calcium aluminate cement (CAC) or calcium silicate based hydrauliccements, for example, Portland cement. CSA cements are hydraulic cementsbased on calcium sulfoaluminate, rather than calcium aluminates whichare the basis of CAC cement or calcium silicates which are the basis ofPortland cement. Calcium sulfoaluminate cements are made from clinkersthat include Ye'elimite (Ca₄(AlO₂)₆SO₄ or C₄A₃{hacek over (S)}) as aprimary phase.

Other major phases present in the preferred calcium sulfoaluminatecement may include one or more of the following: dicalcium silicate(C₂S), tetracalcium aluminoferrite (C₄AF), and calcium sulfate (C{hacekover (S)}). The relatively low lime requirement of calciumsulfoaluminate cements compared to Portland cement reduces energyconsumption and emission of green house gases from cement production. Infact, calcium sulfoaluminate cements can be manufactured at temperaturesapproximately 200° C. lower than Portland cement, thus further reducingenergy and green house gas emissions. The amount of Ye'elimite phase(Ca₄(AlO₂)₆SO₄ or C₄A₃{hacek over (S)}) present in the calciumsulfoaluminate cements useful in some embodiments of this invention ispreferably about 20 to about 90 wt %, more preferably about 30 to about75 wt %, and most preferably about 40 to about 60 wt %.

Preferable compositions of the present invention comprise about 1 toabout 200 parts, more preferably about 2.5 to about 100 parts, even morepreferably about 2.5 to about 50 parts, and still more preferably about5 to about 30 parts by weight calcium sulfoaluminate cement, pbw per 100pbw of thermally activated aluminosilicate mineral.

The amount of calcium sulfoaluminate cement used in the compositions ofsome embodiments of the invention is adjustable based on the amount ofactive Ye'elimite phase (Ca₄(AlO₂)₆SO₄ or C₄A₃{hacek over (S)}) presentin the CSA cement.

Portland Cement

The dimensionally stable geopolymer compositions of some embodiments ofthe present invention comprising aluminosilicate mineral, alkali metalchemical activator, calcium sulfoaluminate cement and calcium sulfatethat demonstrate extremely low magnitudes of material shrinkage. Itwould then be logical and natural to expect that if another bindermaterial with good dimensional stability were additionally incorporatedinto the inventive mixture, the overall material shrinkage anddimensional stability of the resulting composition would still remainlow and acceptable. For example, the shrinkage of pure Portland cementbased cementitious compositions has been determined to be almost anorder of magnitude lower than the shrinkage of geopolymer binderscomposed of fly ash activated with an alkali metal citrate. However,very surprisingly, it has been discovered that addition of Portlandcement to the dimensionally stable compositions of the present inventioncomprising aluminosilicate mineral, alkali metal chemical activator,calcium sulfoaluminate cement and calcium sulfate has a negativeinfluence on the shrinkage behavior of resulting compositions. It hasbeen found that addition of Portland cement to the geopolymercompositions of the present invention increases the shrinkage of theresulting compositions. The magnitude of observed shrinkage increaseswith increase in the amount of Portland cement in the resultingcompositions. This result is highly unexpected and surprising and itunderscores the extremely complex nature of chemical interactions thatoccur when other types of cements and/or chemical additives areintroduced to the dimensionally stable geopolymer binder compositions ofthe present invention. Based on this understanding, no Portland cementis incorporated in some preferred embodiments of the invention. However,it is contemplated that some amount of Portland cement be used in someembodiments when desired in situations where some increase in shrinkagebehavior may be acceptable. The practical limit of amount of Portlandcement will depend on the amount of adverse effect on shrinkage behaviorthat may be acceptable, but in some preferred embodiments of theinvention, no more than 15 parts by weight of Portland cement per 100parts by weight of the thermally activated aluminosilicate mineral isincluded.

The low cost and widespread availability of the limestone, shales, andother naturally occurring materials make Portland cement one of thelowest-cost materials widely used over the last century throughout theworld.

As used herein, “Portland cement” is a calcium silicate based hydrauliccement. ASTM C 150 defines Portland cement as “hydraulic cement (cementthat not only hardens by reacting with water but also forms awater-resistant product) produced by pulverizing clinkers consistingessentially of hydraulic calcium silicates, usually containing one ormore of the forms of calcium sulfate as an inter ground addition.” Asused herein, “clinkers” are nodules (diameters, about 0.2 to about 1.0inch [5-25 mm]) of a sintered material that are produced when a rawmixture of predetermined composition is heated to high temperature.

Calcium Aluminate Cement

Calcium aluminate cement (CAC) is another type of hydraulic cement thatmay form a component of the reactive powder blend of some embodiments ofthe invention when particularly higher compressive strength is notrequired with low water content slurries containing substantial amountsof fly ash.

Calcium aluminate cement (CAC) is also commonly referred to as aluminouscement or high alumina cement. Calcium aluminate cements have a highalumina content, about 30-45 wt % is preferable. Higher purity calciumaluminate cements are also commercially available in which the aluminacontent can range as high as about 80 wt %. These higher purity calciumaluminate cements tend to be very expensive relative to other cements.The calcium aluminate cements used in the compositions of someembodiments of the invention are finely ground to facilitate entry ofthe aluminates into the aqueous phase so that rapid formation ofettringite and other calcium aluminate hydrates can take place. Thesurface area of the calcium aluminate cement that useful in suchembodiments will be greater than about 3,000 cm²/gram and preferablyabout 4,000 to about 6,000 cm²/gram as measured by the Blaine surfacearea method (ASTM C 204).

Several manufacturing methods have emerged to produce calcium aluminatecement worldwide. Preferably, the main raw materials used in themanufacturing of calcium aluminate cement are bauxite and limestone. Onemanufacturing method for producing calcium aluminate cement is describedas follows. The bauxite ore is first crushed and dried, then groundalong with limestone. The dry powder comprising of bauxite and limestoneis then fed into a rotary kiln. A pulverized low-ash coal is used asfuel in the kiln. Reaction between bauxite and limestone takes place inthe kiln and the molten product collects in the lower end of the kilnand pours into a trough set at the bottom. The molten clinker isquenched with water to form granulates of the clinker, which is thenconveyed to a stock-pile. This granulate is then ground to the desiredfineness to produce the final cement.

Typically, several calcium aluminate compounds may be formed during themanufacturing process of calcium aluminate cement. The predominantcompound formed often is monocalcium aluminate (CaO.Al₂O₃, also referredto as CA). The other calcium aluminate and calcium silicate compoundsthat are formed can include 12CaO.7Al₂O₃ also referred to as C₁₂A₇,CaO.2Al₂O₃ also referred as CA₂, dicalcium silicate (2CaO.SiO₂, calledC₂S), dicalcium alumina silicate (2CaO.Al₂O₃. SiO₂, called C₂AS).Several other compounds containing relatively high proportion of ironoxides also can be formed. These include calcium ferrites such asCaO.Fe₂O₃ or CF and 2CaO.Fe₂O₃ or C₂F, and calcium alumino-ferrites suchas tetracalcium aluminoferrite (4CaO.Al₂O₃.Fe₂O₃ or C₄AF),6CaO.Al₂O₃.2Fe₂O₃ or C₆AF₂) and 6CaO.2Al₂O₃.Fe₂O₃ or C₆A₂F). Other minorconstituents often present in the calcium aluminate cement includemagnesia (MgO), titanic (TiO₂), sulfates and alkalis.

The calcium aluminate cements can have one or more of the aforementionedphases. Calcium aluminate cements having monocalcium aluminate(CaO.Al₂O₃ or CA) and/or dodeca calcium hepta aluminate (12CaO.7Al₂O₃ orC₁₂A₇) as predominant phases are particularly preferred in someembodiments of the present invention. Further, the calcium aluminatephases can be available in crystalline form and/or amorphous form.Ciment Fondu (or HAC Fondu), Secar 51, and Secar 71 are some examples ofcommercially available calcium aluminate cements that have themonocalcium aluminate (CA) as the primary cement phase. Ternal EV is anexample of commercially available calcium aluminate cement that has thedodeca calcium hepta aluminate (12CaO.7Al₂O₃ or C₁₂A₇) as thepredominant cement phase.

When calcium aluminate (CAC) cements are used in the present invention,they may partially substitute calcium sulfoaluminate cement. The amountof calcium aluminate cement substitution in the composition of someembodiments of the invention is up to about 49 wt % of the aggregatedweight of calcium sulfoaluminate cement and calcium aluminate cement.

Calcium Fluoroaluminate

Calcium fluoroaluminate has the chemical formula 3CaO.3Al₂O₃.CaF₂.Generally, calcium fluoroaluminate is produced by mixing lime, bauxiteand fluorspar in such an amount that the mineral of the resultingproduct becomes 3CaO.3Al₂O₃.CaF₂ and burning the resulting mixture at atemperature of 1,200°-1,400° C. Calcium fluoroalumniate cements mayoptionally be used in the present invention but generally are notpreferred in many embodiments.

Calcium Sulfate

Calcium sulfate forms an ingredient of the geopolymer bindercompositions of certain embodiments of the present invention. Althoughcalcium sulfate e.g. calcium sulfate dihydrate will react with water, itdoes not form a water resistant product and it is not considered to behydraulic cement for purposes of this invention. Preferred calciumsulfate types that are useful in the present invention include calciumsulfate dihydrate, calcium sulfate hemihydrate and anhydrous calciumsulfate (sometimes called calcium sulfate anhydrite). These calciumsulfates can be from naturally available sources or producedindustrially. When employed as discussed herein, calcium sulfates cansynergistically interact with the other fundamental components of thecementitious compositions of preferred embodiments of the invention andthereby help to minimize material shrinkage while imparting other usefulproperties to the final material.

Different morphological forms of calcium sulfate can be usefullyemployed in various embodiments of the present invention. The propertiesof the geopolymer binders and composites of such embodiments of theinvention have been found to depend significantly on the type of calciumsulfate used based on its chemical composition, particle size, crystalmorphology, and chemical and thermal treatment. Among other properties,the setting behavior, rate of strength development, ultimate compressivestrength, shrinkage behavior, and cracking resistance of the geopolymerbinders of such embodiments can be tailored by selecting an appropriatesource of calcium sulfate in the formulation. Thus, the selection of thetype of calcium sulfate used in the compositions of those embodiments isbased on the balance of properties sought in the end application.

While all three forms of calcium sulfate (primarily hemihydrate,dihydrate and anhydrite) are useful in the four-reactive-componentmixtures of some embodiments of the invention to afford the benefits oflonger setting times and higher compressive strengths than ComparativeExamples 1-4 below containing only two or three of the reactivecomponents, the three different calcium sulfate forms have been found tohave different and surprising effects relative to each other on settingtimes and compressive strengths in various embodiments of the invention.

It is well known that the most soluble chemical form of calcium sulfateis the hemihydrate, followed by the relatively lower solubility form ofthe dihydrate, and then followed by the relatively insoluble form of theanhydrite. All three forms are themselves known to set (form matrices ofthe dihydrate chemical form) in aqueous media under appropriateconditions, and the setting times and compressive strengths of the setforms are known to follow their order of solubility. For example, allother things being equal, employed alone as the sole setting material,the hemihydrate usually has the shortest set times and the anhydrite thelongest set times (typically very long set times).

Quite surprisingly, it has been found that embodiments employingpredominately or all calcium sulfate hemihydrate have the longest settimes, while those employing predominately or all calcium sulfateanhydrite have the shortest set times. Similarly surprisingly, variousembodiments employing predominately or all anhydrous calcium sulfate(anhydrite) have greater early compressive strength, than embodimentsemploying primarily dihydrate form.

In the geopolymer compositions of other embodiments, a blend of two ormore types of calcium sulfate also may be employed to modify the settimes and early compressive strength properties of the compositionrelative to those embodiments using predominately or all of single typeof calcium sulfate. When such a blend is used, the types of calciumsulfate utilized may vary depending upon their chemical composition,particle size, crystal shape and morphology, and/or surface treatment.

Particle size and morphology of calcium sulfate used have been found tosignificantly influence the development of early age and ultimatestrengths of the geopolymer cementitious binder compositions of someembodiments of the invention. In general, a smaller particle size ofcalcium sulfate has been found to provide a more rapid development inearly age strength. When it is desirable to have an extremely rapid rateof strength development, the preferred average particle size of calciumsulfate ranges from about 1 to about 100 microns, more preferably fromabout 1 to about 50 microns, and most preferably from about 1 to about20 microns. Furthermore, calcium sulfates with finer particle size havealso been found to reduce material shrinkage.

It has further been found that for a given amount of calciumsulfoaluminate cement and other raw material components present, anincrease (but not excessive increase) in the amount of calcium sulfateleads to increase in the early age compressive strength of thegeopolymer binders of some embodiments of the present invention. Themost dramatic increase in the early age compressive strength resultswhen the calcium sulfate amount is about 10 to about 50% by weight ofcalcium sulfoaluminate cement.

It has also been unexpectedly found the amount of calcium sulfatepresent in proportion to calcium sulfoaluminate cement in the mixturehas a significant influence on the degree of material shrinkage ofgeopolymer compositions of some embodiments of the invention.Preferably, those embodiments have a calcium sulfate amount of about 5to about 200 parts by weight relative to 100 parts by weight of calciumsulfoaluminate cement. For most effective control on material shrinkageof the geopolymer compositions in such embodiments, the amount ofcalcium sulfate is about 10 to about 100 parts by weight relative to 100parts by weight of calcium sulfoaluminate cement, more preferably about15 to about 75 parts by weight relative to 100 parts by weight ofcalcium sulfoaluminate cement, and most preferably about 20 to about 50parts by weight relative to 100 parts by weight of calciumsulfoaluminate cement.

For given amounts of alkali metal activator and other raw materialcomponents in the composition of some embodiments of the invention,usage of calcium sulfate dihydrate has been found to provide the mosteffective control in minimizing the material shrinkage. Usage ofanhydrous calcium sulfate (anhydrite) and calcium sulfate hemihydratealso provide excellent control in lowering the material shrinkage of thegeopolymer cementitious binder compositions of such embodiments.

The selection of the type or types of calcium sulfate employed in thecompositions of such embodiments is based on the desired rate of earlyage strength development, shrinkage control, and balance of otherproperties sought in the end application.

A part or the entire amount of calcium sulfate can be added as anadditive component of the calcium sulfoaluminate cement in thecompositions of many such embodiments. When this is the case, the amountof calcium sulfate added separately in the composition is reduced by anequivalent amount included in the calcium sulfoaluminate cement.

Calcium sulfate may also be included in the fly ash in some embodimentsof the composition. When such is the case, the amount of calcium sulfateadded separately in the composition may be reduced.

The amount of calcium sulfate added separately to the compositions ofsome embodiments of the invention may be adjusted based on theavailability of the sulfate ions contributed by other ingredientspresent in the mixture.

Pozzolans

Other optional silicate and aluminosilicate minerals which are pozzolanspossessing substantial, little or no cementing properties on their ownin an aqueous media can be included as optional mineral additives in thecompositions of some embodiments of the invention. Various natural andman-made materials have been referred to as pozzolanic materialspossessing pozzolanic properties. Some examples of pozzolanic materialsinclude silica fume, pumice, perlite, diatomaceous earth, finely groundclay, finely ground shale, finely ground slate, finely ground glass,volcanic tuff, trass, and rice husk. All of these pozzolanic materialscan be used either singly or in combined form as part of thecementitious reactive powder of some embodiments of the invention.

Fillers-Aggregates, Inorganic Mineral Fillers and Lightweight Fillers

While the disclosed cementitious reactive powder blend defines the rapidsetting component of the cementitious composition of many embodiments ofthe invention, it will be understood by those skilled in the art thatother materials may be included in the composition depending on itsintended use and application.

One or more fillers such as sand, fine aggregate, coarse aggregate,inorganic mineral fillers, lightweight fillers may be used as acomponent in the geopolymeric formulations of some embodiments of theinvention. In such embodiments, these fillers preferably are notpozzolans or thermally activated aluminosilicate minerals.

Preferable inorganic mineral fillers in such embodiments are dolomite,limestone, calcium carbonate, ground clay, shale, slate, mica and talc.Generally, such fillers they have a fine particle size with preferableaverage particle diameter of less than about 100 microns, preferablyless than about 50 microns, and more preferably less than about 25microns in the compositions of some embodiments of the invention.Smectite clays and palygorskite and their mixtures are not consideredsuitable inorganic mineral fillers when used in substantial quantitiesfor the purposes this invention.

As used herein, fine aggregate or sand is defined as an inorganic rockmaterial typically with an average particle size of less than about 4.75mm (0.195 inches) (although other sizes may be used depending on theapplication). Preferable sand in the invention has a mean particle sizeof about 0.1 mm to about 2 mm. Fine sand with a mean particle size ofabout 1 mm or less is preferred filler in some embodiments of theinvention.

Sands having a maximum particle diameter of about 0.6 mm, preferably atmost about 0.425 mm, a mean particle diameter within a range of about0.1 to about 0.5 mm, preferably about 0.1 mm to about 0.3 mm are used inother embodiments of the invention. Examples of preferable fine sandinclude QUIKRETE FINE No. 1961 and UNIMIN 5030 having a predominant sizerange of US sieve number #70-#30 (0.2-0.6 mm).

The particle size distribution and amount of sand in the formulationassists in controlling the rheological behavior of the embodimentsincorporating sands. Fine sand may be added in the geopolymericcementitious compositions of some embodiments at sand/cementitiousmaterials (reactive powder) ratio of about 0.05 to about 4. When it isdesired to achieve self-leveling material rheology, the most desirablesand to cementitious materials ratio in the formulation is in the rangeof about 0.50 to about 2, most preferably about 0.75 to about 1.5.

Coarse aggregate is defined as an inorganic rock material with anaverage particle size at least about 4.75 mm (0.195 inches), for exampleabout ¼′ inch to about 1½ inch (0.64 to 3.81 cm) (although other sizesmay be used depending on the specific application). Aggregate with sizelarger than about 1½ inch (3.81 cm) may also be used in someapplications, for example, concrete pavement. The particle shape andtexture of the coarse aggregate can have a variety of configurations,such as angular, rough-textured, elongated, rounded or smooth or acombination of these.

Preferable coarse aggregates are made of minerals such as granite,basalt, quartz, riolite, andesite, tuff, pumice, limestone, dolomite,sandstone, marble, chert, flint, greywacke, slate, and/or gnessis.Coarse aggregate useful in some embodiments of this invention preferablymeet the specifications set out in ASTM C33 (2011) and AASHTO M6/M80(2008) standards.

When coarse aggregates are included in the geopolymeric cementitiouscompositions of some embodiments of the invention, they are preferablyemployed at an aggregate to cementitious materials (reactive powder)ratio of about 0.25 to about 5. Some embodiments of the inventioncontain coarse aggregate with coarse aggregate to cementitious materialsratio of about 0.25 to about 1. Some other embodiments of the inventioncontain coarse aggregate with coarse aggregate to cementitious materialsratio of about 1 to about 3.

Lightweight fillers have a specific gravity of less than about 1.5,preferably less than about 1, more preferably less than about 0.75, andmost preferably less than about 0.5. In some other preferred embodimentsof the invention the specific gravity of lightweight fillers is lessthan about 0.3, more preferably less than about 0.2 and most preferablyless than about 0.1. In contrast, inorganic mineral fillers preferablyhave a specific gravity above about 2.0. Examples of useful lightweightfillers are pumice, vermiculite, expanded forms of clay, shale, slateand perlite, scoria, expanded slag, cinders, glass microspheres,synthetic ceramic microspheres, hollow ceramic microspheres, lightweightpolystyrene beads, plastic hollow microspheres, expanded plastic beads,and the like. Expanded plastic beads and hollow plastic spheres whenused in the composition of some embodiments of the invention areemployed in appropriate quantities on a weight basis in view of theirrelatively low specific gravity and the specific application.

When lightweight fillers are utilized to reduce the weight of someembodiments of the invention, they may be employed, for example, as afiller to cementitious materials (reactive powder) ratio of about 0.01to about 2, preferably about 0.01 to about 1. A combination of two ormore types of lightweight fillers also may be useful in such embodimentsof the invention.

While some embodiments of the invention contain only sand as the addedfiller, other embodiments contain sand and inorganic mineral fillersand/or lightweight filler. Other embodiments may utilize inorganicmineral filler and lightweight fillers as the added fillers. Yet, otherembodiments incorporate sand, inorganic mineral filler and lightweightfiller as added fillers. Still other embodiments contain only inorganicmineral fillers or lightweight fillers and no sand, fine aggregate orcoarse aggregate. Embodiments of the invention containing coarseaggregate, in addition, can include or exclude one of more of thefollowing fillers—sand, lightweight filler, and inorganic mineralfiller. Yet other embodiments are substantially free of any addedfillers.

Alkali Metal Chemical Activators.

Alkali metal salts and bases are useful as chemical activators toactivate the Reactive Powder Component A comprising thermally activatedaluminosilicate mineral such as fly ash, calcium sulfoaluminate cementand calcium sulfate. The alkali metal activators used in someembodiments of this invention can be added in liquid or solid form. Thepreferred alkali metal chemical activators of such embodiments of thisinvention are metal salts of organic acids. The more preferred alkalimetal chemical activators are alkali metal salts of carboxylic acids.Alkali metal hydroxides and alkali metal silicates are some otherexamples of alkali metal chemical activator useful in some embodimentsof this invention. Alternatively, alkali metal hydroxides and alkalimetal silicates can also be useful in combination with carboxylic acidssuch as citric acid to provide chemical activation of reactive powderblend comprising thermally activated aluminosilicate mineral, calciumsulfoaluminate cement and calcium sulfate.

In some embodiments of the present invention, employing alkali metalsalts of citric acid such as sodium or potassium citrate in combinationwith reactive powder blend comprising thermally activatedaluminosilicate mineral, calcium sulfoaluminate cement, and calciumsulfate, provides mixture compositions with relatively good fluidity andwhich do not stiffen too quickly, after mixing the raw materials at oraround ambient temperatures (about 20-25° C.).

The amount of alkali metal salt of citric acid, e.g. potassium citrateor sodium citrates, is about 0.5 to about 10 wt. %, preferably about 1to about 6 wt. %, preferably about 1.25 to about 4 wt. %, morepreferably about 1.5 to about 2.5 wt. % and most preferably about 2 wt %based on 100 parts of the cementitious reactive components (i.e.,Reactive Powder Component A) of some embodiments of the invention. Thus,for example, for 100 pounds of cementitious reactive powder, there maybe about 1.25 to about 4 total pounds of potassium and/or sodiumcitrates. The preferred alkali metal citrates are potassium citrates andsodium citrates and particularly tri-potassium citrate monohydrate, andtri-sodium citrate anhydrous, tri-sodium citrate monohydrate, sodiumcitrate dibasic sesquihydrate, tri-sodium citrate dihydrate, di-sodiumcitrate, and mono-sodium citrate.

Preferably the set activator does not contain an alkanolamine. Also,preferably the activator does not contain a phosphate.

Set Retarders

Organic compounds such as hydroxylated carboxylic acids, carbohydrates,sugars, and starches are the preferred retarders of some embodiments ofthe present invention. Organic acids such as citric acid, tartaric acid,malic acid, gluconic acid, succinic acid, glycolic acid, malonic acid,butyric acid, malic acid, fumaric acid, formic acid, glutamic acid,pentanoic acid, glutaric acid, gluconic acid, tartronic acid, mucicacid, tridydroxy benzoic acid, etc. are useful as set retarders in thedimensionally stable geopolymer cementitious binder compositions of somepreferred embodiments.

Sodium gluconate also is useful as organic set retarder in someembodiments of the present invention. Cellulose based organic polymerssuch as hydroxyethyl-cellulose (HEC), hydroxypropyl-cellulose (HPC),hydroxypropylmethyl-cellulose (HPMC), ethyl-cellulose (EC),methylethyl-cellulose (MEC), carboxymethyl-cellulose (CMC),carboxymethylethyl-cellulose (CMEC), carboxymethylhydroxyethyl-cellulose(CMHEC) are additional useful retarders in some of the compositions ofthe present invention.

These cellulose based retarders when added to the composition of someembodiments of the invention significantly increase the viscosity of themix in addition to causing retardation. Preferably, inorganic acid basedretarders such as borates or boric acid are not employed in significantamounts in some preferred embodiments of the invention because theyhinder mix rheology, cause excessive efflorescence, and reduce materialbond strength to other substrates.

Other Optional Set-Control Agents

Other optional set control chemical additives include a sodiumcarbonate, potassium carbonate, calcium nitrate, calcium nitrite,calcium formate, calcium acetate, calcium chloride, lithium carbonate,lithium nitrate, lithium nitrite, aluminum sulfate, sodium aluminate,alkanolamines, polyphosphates, and the like. These additives whenincluded as a part of the formulation may also influence rheology of thegeopolymer binder compositions of some embodiments of the invention inaddition to affecting their setting behavior.

Optional Materials, Fibers, and Scrims

Other optional materials and additives may be included in geopolymerbinder compositions of some embodiments of the invention. These includeat least one member selected from the group consisting of film-formingredispersible polymer powders, film-forming polymer latex dispersions,defoaming and antifoaming agents, water retaining additives, set controlagents, shrinkage reducing admixtures, foaming and air entrainingagents, organic and inorganic rheology control agents, viscositymodifying agents (thickeners), efflorescence control (suppression)agents, corrosion control agents, wetting agents, colorants and/orpigments, discrete fibers, long and continuous fibers and reinforcement,textile reinforcement, polyvinyl alcohol fibers, and/or glass fibersandor other discrete reinforcing fibers.

Discrete reinforcing fibers of different types may be incorporated inthe cementitious board compositions made pursuant to certain embodimentsof the invention. Scrims made of materials such as polymer-coated glassfibers and polymeric materials such as polypropylene, polyethylene andnylon are examples of materials that can be used to reinforce thecement-based product depending upon its function and application.

Preferably the geopolymer binders of many preferred embodiments of theinvention do not contain significant amounts of cement kiln dust. Cementkiln dust (CKD) can be created in the kiln during the production ofcement clinker. The dust is a particulate mixture of partially calcinedand unreacted raw feed, clinker dust and ash, enriched with alkalisulfates, halides and other volatiles. These particulates are capturedby the exhaust gases and collected in particulate matter control devicessuch as cyclones, baghouses and electrostatic precipitators.

CKD consists primarily of calcium carbonate and silicon dioxide which issimilar to the cement kiln raw feed, but the amount of alkalies,chloride and sulfate is usually considerably higher in the dust. CKDfrom three different types of operations: long-wet, long-dry, and alkaliby-pass with precalciner have various chemical and physical traits. CKDgenerated from long-wet and long-dry kilns is composed of partiallycalcined kiln feed fines enriched with alkali sulfates and chlorides.The dust collected from the alkali by-pass of precalciner kilns tend tobe coarser, more calcined, and also concentrated with alkali volatiles.However, the alkali by-pass process contains the highest amount byweight of calcium oxide and lowest loss on ignition (L01). Table fromAdaska et al., Beneficial Uses of Cement Kiln Dust, presented at 2008IEEE/PCA 50th Cement Industry Technical Conf., Miami, Fla., May 19-22,2008, provides the composition breakdown for the three different typesof operation and includes a preferable chemical composition for Type IPortland cement for comparison.

TABLE G Examples of Compositions of CKD from Different Operation SourcesAlkali by-pass from Typical Type I Long-wet Long-dry preheater/ PortlandConstit- kiln (% by kiln (% by precalciner cement (% uent weight)weight) (% by weight) by weight) SiO2 15.02 9.64 15.23 20.5 AL2O3 3.853.39 3.07 5.4 Fe2O3 1.88 1.10 2.00 2.6 CaO 41.01 44.91 61.28 63.9 MgO1.47 1.29 2.13 2.1 SO3 6.27 6.74 8.67 3.0 K2O 2.57 2.40 2.51 <1 Loss on25.78 30.24 4.48 0-3 Ignition (LOI) Free lime 0.85 0.52 27.18 <2 (CaO)

Superplasticizers and Air Entraining Agents

Water reducing agents (superplasticizers), are preferably used in thecompositions of some embodiments of the invention. They may be added inthe dry form or in the form of a solution. Superplasticizers can help toreduce water demand of the mixture. Examples of superplasticizersinclude polynapthalene sulfonates, polyacrylates, polycarboxylates,polyether polycarboxylates, lignosulfonates, melamine sulfonates,caesins, and the like. Depending upon the type of superplasticizer used,the weight ratio of the superplasticizer (on dry powder basis) to thereactive powder blend preferably will be about 5 wt % or less,preferably about 2 wt. % or less, preferably about 0.1 to about 1 wt. %.

Superplasticizers based on polycarboxylate polyether chemistry are themost preferred water reducing chemical admixture for some embodiments ofthe invention. Polycarboxylate polyether superplasticizers are the mostpreferred since they facilitate accomplishment of the various objectivesof this invention as mentioned earlier.

Air entraining agents are added to the cementitious slurry of someembodiments of the invention to form air bubbles (foam) in situ. Airentraining agents are preferably surfactants used to purposely trapmicroscopic air bubbles in the concrete. Alternatively, air entrainingagents are employed to externally produce foam which is introduced intothe mixtures of the compositions of some embodiments during the mixingoperation to reduce the density of the product. Preferably to externallyproduce foam the air entraining agent (also known as a liquid foamingagent), air and water are mixed to form foam in a suitable foamgenerating apparatus. A foam stabilizing agent such as polyvinyl alcoholcan be added to the foam before the foam is added to the cementitiousslurry.

Examples of air entraining/foaming agents include alkyl sulfonates,alkylbenzolfulfonates and alkyl ether sulfate oligomers among others.Details of the general formula for these foaming agents can be found inU.S. Pat. No. 5,643,510 incorporated herein by reference.

An air entraining agent (foaming agent) such as that conforming tostandards as set forth in ASTM C 260 “Standard Specification forAir-Entraining Admixtures for Concrete” (Aug. 1, 2006) can be employed.Such air entraining agents are well known to those skilled in the artand are described in the Kosmatka et al “Design and Control of ConcreteMixtures,” Fourteenth Edition, Portland Cement Association, specificallyChapter 8 entitled, “Air Entrained Concrete,” (cited in US PatentApplication Publication No. 2007/0079733 A1).

Commercially available air entraining materials include vinsol woodresins, sulfonated hydrocarbons, fatty and resinous acids, aliphaticsubstituted aryl sulfonates, such as sulfonated lignin salts andnumerous other interfacially active materials which normally take theform of anionic or nonionic surface active agents, sodium abietate,saturated or unsaturated fatty acids and salts thereof, tensides,alkyl-aryl-sulfonates, phenol ethoxylates, lignosulfonates, resin soaps,sodium hydroxystearate, lauryl sulfate, ABSs (alkylbenzenesulfonates),LASs (linear alkylbenzenesulfonates), alkanesulfonates, polyoxyethylenealkyl(phenyl)ethers, polyoxyethylene alkyl(phenyl)ether sulfate estersor salts thereof, polyoxyethylene alkyl(phenyl)ether phosphate esters orsalts thereof, proteinic materials, alkenylsulfosuccinates,alpha-olefinsulfonates, a sodium salt of alpha olefin sulphonate, orsodium lauryl sulphate or sulphonate and mixtures thereof.

Preferably the air entraining (foaming) agent is about 0.01 to about 1wt. % of the weight of the overall cementitious composition.

Bio-Polymers and Organic Rheology Control Agents

Succinoglycans, diutan gum, guar gum, wellan gum, xanthan gums andcellulose ether based organic compounds, are bio-polymers that act ashydrocolloids and rheology control agents in some embodiments of theinvention. Synthetic organic polymers such as polyacryl amides,alkali-swellable acrylic polymers, associative acrylic polymers,acrylic/acrylamid copolymers, hydrophobically modified alkali-swellablepolymers, highly water-swellable organic polymers can be usefullyemployed as rheology control agents and thickneners in the geopolymerbinder compositions of such embodiments.

Both associative and non-associative types of rheology control agentsand thickeners can be usefully employed in the geopolymer bindercompositions of such embodiments. Examples of cellulose based organicpolymers useful for rheology control in the geopolymer compositions ofthose embodiments of the present invention includehydroxyethyl-cellulose (HEC), hydroxypropyl-cellulose (HPC),hydroxypropylmethyl-cellulose (HPMC), ethyl-cellulose (EC),methylethyl-cellulose (MEC), carboxymethyl-cellulose (CMC),carboxymethylethyl-cellulose (CMEC), carboxymethylhydroxyethyl-cellulose(CMHEC). The organic rheology control agents and thickeners mentionedabove are soluble both in cold and hot water. These additives also actas water retention agents and thereby minimize material segregation andbleeding in addition to controlling the material rheology.

Inorganic Rheology Control Agents

The geopolymer cementitious compositions of some embodiments of theinvention may also include inorganic rheology control agents belongingto the family of phyllosilicates. Examples of inorganic rheology controlagents particularly useful in those embodiments may includepalygorskite, sepiolite, smectites, kaolinites, and illite. Examples ofparticularly useful smectite clays are hectorite, saponite, andmontmorillonite. Different varieties of bentonite clays both natural andchemically treated may also be used to control rheology of thecompositions of those embodiments. Such additives also act as waterretention agents and thereby minimize material segregation and bleeding.The inorganic rheology control agents may be added in the absence of orin combination with the organic rheology control agents.

Film-Forming Polymer Additives

Preferable film-forming redispersible polymer powders in someembodiments of the invention are latex powders. These polymer powdersare water-redispersible and produced by spray-drying of aqueous polymerdispersions (latex).

Latex is an emulsion polymer. Latex is a water based polymer dispersion,widely used in industrial applications. Latex is a stable dispersion(colloidal emulsion) of polymer microparticles in an aqueous medium.Thus, it is a suspension/dispersion of rubber or plastic polymermicroparticles in water. Latexes may be natural or synthetic.

The latex is preferably made from a pure acrylic, a styrene rubber, astyrene butadiene rubber, a styrene acrylic, a vinyl acrylic or anacrylated ethylene vinyl acetate copolymer and is more preferably a pureacrylic. Preferably latex polymer is derived from at least one acrylicmonomer selected from the group consisting of acrylic acid, acrylic acidesters, methacrylic acid, and methacrylic acid esters. For example, themonomers preferably employed in emulsion polymerization include suchmonomers as methyl acrylate, ethyl acrylate, methyl methacrylate, butylacrylate, 2-ethyl hexyl acrylate, other acrylates, methacrylates andtheir blends, acrylic acid, methacrylic acid, styrene, vinyl toluene,vinyl acetate, vinyl esters of higher carboxylic acids than acetic acid,e.g. vinyl versatate, acrylonitrile, acrylamide, butadiene, ethylene,vinyl chloride and the like, and mixtures thereof.

For example, a latex polymer can be a butyl acrylate/methyl methacrylatecopolymer or a 2-ethylhexyl acrylate/methyl methacrylate copolymer.Preferably, the latex polymer is further derived from one or moremonomers selected from the group consisting of styrene, alpha-methylstyrene, vinyl chloride, acrylonitrile, methacrylonitrile, ureidomethacrylate, vinyl acetate, vinyl esters of branched tertiarymonocarboxylic acids, itaconic acid, crotonic acid, maleic acid, fumaricacid, ethylene, and C4-C8 conjugated dienes.

Efflorescence Suppression Agent

Water repelling agents such as silanes, silicones, siloxanes, stearatescan be added to the cementitious compositions of some embodiments of theinvention to reduce efflorescence potential of the material. Selectedexamples of useful efflorescence suppression agents includeoctyltriethoxy silane, potassium methyl siliconate, calcium stearate,butyl stearate, polymer stearates. These efflorescence control agentsreduce the transport of the water within the hardened material andthereby minimize migration of salts and other soluble chemicals that canpotentially cause efflorescence. Excessive efflorescence can lead topoor aesthetics, material disruption and damage from expansive reactionsoccurring due to salt accumulation and salt hydration, and reduction inbond strength with other substrates and surface coatings.

Defoaming Agents

Defoaming agents can be added to the geopolymer cementitiouscompositions of some embodiments of the invention to reduce the amountof entrapped air, increase material strength, increase material bondstrength to other substrates, and to produce a defect free surface inapplications where surface aesthetics is an important criteria. Examplesof suitable defoaming agents useful in the geopolymer compositions ofsome embodiments of the invention include polyethylene oxides,polyetheramine, polyethylene glycol, polypropylene glycol, alkoxylates,polyalkoxylate, fatty alcohol alkoxylates, hydrophobic esters, tributylphosphate, alkyl polyacrylates, silanes, silicones, polysiloxanes,polyether siloxanes, acetylenic diols, tetramethyl decynediol, secondaryalcohol ethoxylates, silicone oil, hydrophobic silica, oils (mineraloil, vegetable oil, white oil), waxes (paraffin waxes, ester waxes,fatty alcohol waxes), amides, fatty acids, polyether derivatives offatty acids, etc.

Initial Slurry Temperature

In some embodiments of the present invention, it is preferred to formthe slurry under conditions which provide a reduced initial bindermixture slurry temperature and rise of less than about 50° F. (28° C.)to a final binder mixture slurry temperature, more preferably a rise ofless than about 40° F. (22° C.) and most preferably a rise of less thanabout 30° F. (17° C.) for improved temperature stability and moreimportantly, slower gelation and final setting times of from about 10 toabout 240 minutes, more preferably about 60 to about 120 minutes andmost preferably about 30 to about 60 minutes, allows for more controlledworking time for commercial use of the binder compositions. The initialslurry temperature is preferably about room temperature.

Increasing the initial temperature of the slurry increases the rate oftemperature rise as the reactions proceed and reduces the setting time.Thus, initial slurry temperature of 95° F. (35° C.) to 105° F. (41.1°C.) used in preparing conventional fly ash based geopolymeric bindercompositions for rapid gelation and setting times is preferably avoidedin some embodiments of the invention, since the composition formulationis designed to reduce temperature increase behavior of the mixture fromthe initial slurry temperatures. The benefit of the thermal stabilityobtained with many embodiments of the present invention for increasingthe time for initial gelation and final setting times, which, in turn,provides for increased commercially workability of the composition, maybe somewhat lessened if the initial slurry temperature is alreadyrelatively high.

The “initial temperature” is defined as the temperature of the overallmixture during the first minute after the cementitious reactive powder,activator, and water are first all present in the mixture. Of course thetemperature of the overall mixture can vary during this first minutebut, in order to achieve a preferred thermal stability, it will remainwithin an initial temperature range of about 0 to about 50° C., morepreferably an initial temperature range of about 10 to about 35° C.,even more preferably an initial temperature range of about 15 to about25° C., preferably ambient temperature.

Material Exothermic and Temperature Rise Behavior

Compositions of some embodiments of the present invention advantageouslyachieve moderate heat evolution and low temperature rise within thematerial during the curing stage. In such compositions of someembodiments of the invention, the maximum temperature rise occurring inthe material is preferably less than about 50° F. (28° C.), morepreferably less than about 40° F. (22° C.), and most preferably lessthan about 30° F. (17° C.). This prevents excessive thermal expansionand consequent cracking and disruption of material. This aspect becomeseven more beneficial when the material is utilized in a manner wherelarge thicknesses of material pours are involved in actual fieldapplications. The geopolymer cementitious compositions of the presentinvention are beneficial in this particular aspect as they exhibit lowerthermal expansion and enhanced resistance to thermal cracking in actualfield applications.

EXAMPLES

In the examples herein, as mentioned above, percentages of compositionsor product formulae are in weight percentages, unless otherwiseexpressly stated. The reported measurements also in approximate amountsunless expressly stated, e.g. approximate percentages, weights,temperatures, distances or other properties. Also, unless otherwiseindicated FASTROCK 500 brand calcium sulfoaluminate cement, availablefrom CTS Cement Company is employed as a component of cementitiousreactive powder. FASTROCK 500 has an average particle size of about 5microns with 95% of particles finer than about 25 microns. The measuredBlaine fineness of FASTROCK 500 was about 6780 cm²/g. The oxidecomposition of FASTROCK 500 was analyzed and is shown in TABLE AA:

TABLE AA Weight % in Weight % in Oxide FASTROCK 500 Class C fly Ash CaO43.78 24.14 SiO₂ 14.02 36.90 Al₂O₃ 25.23 20.12 Fe₂O₃ 1.05 5.96 SO₃ 8.671.19 MgO 3.23 5.44 Na₂O 1.81 1.73 K₂O 0.32 0.52 TiO₂ 0.76 1.42 P₂O₅ 1.18Loss on Ignition 1.58 0.52

The main phases present in the FASTROCK 500 calcium sulfoaluminatecement employed in the examples include C₄A₃{hacek over (S)}, C₂₋₅,C₄AF, and C{hacek over (S)}.

In all the examples, unless otherwise indicated, the fly ash is Class CFly Ash from Campbell Power Plant, West Olive, Mich. This fly ash has anaverage particle size of about 4 microns. The measured Blaine finenessof the fly ash is about 4300 cm²/g. The oxide composition of the Class Cfly ash employed in these examples is shown in TABLE AA.

The calcium sulfate dihydrate included in a number of examples is afine-grained calcium sulfate dihydrate, termed here as landplaster orfine-grained landplaster, available from the United States GypsumCompany. The fine-grained landplaster has an average particle size ofabout 15 microns.

The anhydrous calcium sulfate (anhydrite) included in some of theexamples is SNOW WHITE brand filler available from the United StatesGypsum Company. The USG SNOW WHITE filler is an insoluble form ofanhydrite produced by high temperature thermal treatment of calciumsulfate, typically gypsum. It has a very low level of chemicallycombined moisture, preferably about 0.35%. The average particle size ofthe USG SNOW WHITE filler is about 7 microns.

The calcium sulfate hemihydrate included in a number of the examples isUSG HYDROCAL C-Base brand calcium sulfate hemihydrate available from theUnited States Gypsum Company. HYDROCAL C-Base is an alpha morphologicalform of calcium sulfate hemihydrate having blocky crystal microstructureand low water demand. The USG HYDROCAL C-Base has an average particlesize of about 17 microns.

Coarse-grained calcium sulfate dihydrate, otherwise identified here ascoarse landplaster or coarse-grained landplaster, employed in a numberof the examples was procured from the United States Gypsum Company withcommercial name USG BEN FRANKLIN AG brand Coarse Gypsum. The USG BENFRANKLIN AG brand gypsum is a coarse grained calcium sulfate dihydratewith an average particle size of about 75 to about 80 microns.

The fine-grained calcium sulfate dihydrate included in a number of theexamples is USG TERRA ALBA F&P brand from the United States GypsumCompany. The USG TERRA ALBA F&P filler is a high-purity calcium sulfatedihydrate with an average particle size of about 13 microns.

The QUIKRETE Fine-grained No. 1961 Fine Sand included in some exampleshas a particle size as shown in TABLE BB:

TABLE BB Percent Passing (%) QUIKRETE FINE Percent Passing (%) SieveSize GRAIN No. 1961 Sand UNIMIN 5030 Sand  30 Mesh 100  40 Mesh 98 100 50 Mesh 69 73  70 Mesh 23 22 100 Mesh 5 4 140 Mesh 1 0 200 Mesh 0

The UNIMIN 5030 Sand included in some examples has a particle size asshown in TABLE BB.

Potassium citrate or sodium citrate is the alkali metal citrate added tosome of the examples of the cementitious compositions of someembodiments of the invention and acts as a chemical activator, rheologymodifier, and set control agent.

The time of initial setting and the time of final setting reportedherein were measured using the ASTM C266 (2008) standard using theGilmore needles.

The slump and flow behavior of the cementitious geopolymer compositionsof some embodiments of this invention are characterized by a slump test.The slump test used herein utilizes a hollow cylinder about 5.08 cm. (2in.) diameter and about 10.16 cm. (4 in.) length held vertically withone open end resting on a smooth plastic surface. The cylinder is filledup to the top with the cementitious mixture followed by striking off thetop surface to remove the excess slurry mixture. The cylinder is thengently lifted up vertically to allow the slurry to come out from thebottom and spread on the plastic surface to form a circular patty. Thediameter of the patty is then measured and recorded as the slump of thematerial. As used herein, compositions with good flow behavior yield alarger slump value. The flow of the slurry is characterized by ratingthe slurry flowability on a scale of 1 to 10 with a value of 1representing a very poor flow behavior and a value of 10 representingexcellent flow behavior.

Material shrinkage (also referred to herein as “shrinkage”) as usedherein is characterized by measuring the length change of prism specimenaccording to the ASTM C928 (2009) test standard. The initial lengthmeasurement is taken 4 hours after the individual raw materialcomponents including water are brought together. The final measurementis taken 8 weeks after the components including water were broughttogether. The difference between the initial and final measurementsdivided by the initial length times 100% gives the shrinkage as apercentage. The 1 in×1 in. (cross-section) length change prism specimensalso referred to herein as bars, are prepared according to the ASTM C157(2008) standard.

Compressive strength of materials as used herein is measured inaccordance to the ASTM C109 (2008) test method by testing the 2 in.×2in.×2 in. cubes to failure under compression. The cubes are demoldedfrom the brass molds after hardening and cured in sealed plastic bagsuntil the age of testing. The cubes are tested at the age of about4-hours, about 24-hours, about 7-days and about 28-days after the cast.In some examples, the cubes are subjected to saturation for 7-days aftercompletion of 28-day curing in plastic bags. These cubes are tested incompression in the saturated condition immediately after taking them outof water and surface drying.

The slurry temperature rise behavior has used herein is measured in thesemi-adiabatic condition by putting the slurry in an insulated containerand recording the material temperature using a thermocouple.

Many of the examples show physical properties of the developedgeopolymer cementitious compositions of some embodiments of theinvention comprising thermally activated aluminosilicate mineral (flyash), calcium sulfoaluminate cement, calcium sulfate and alkali metalchemical activators. This illustrates the influence of incorporatingcalcium sulfoaluminate cement in combination with calcium sulfate andalkali metal chemical activator on the material shrinkage behavior,early age compressive strength, ultimate compressive strength,exothermal behavior and setting characteristics of the developedgeopolymer cementitious compositions of some embodiments of theinvention.

Compositions of some embodiments of the present invention advantageouslyachieve moderate heat evolution and low temperature rise within thematerial during the curing stage. In such compositions, the maximumtemperature rise occurring in the material is preferably less than about50° F. (28° C.), more preferably less than about 40° F. (22° C.) andstill more preferably less than about 30° F. (17° C.). This preventsexcessive thermal expansion and consequent cracking and disruption ofmaterial. This aspect becomes even more beneficial when the material isutilized in a manner where large thicknesses of material pours areinvolved in the actual field applications. The geopolymer cementitiouscompositions of the present invention investigated as discussed beloware beneficial in this particular aspect as they exhibit lower thermalexpansion and enhanced resistance to thermal cracking in actual fieldapplications.

The inventive compositions of some embodiments of the invention alsoachieve long setting times for good workability. An extremely shortsetting time is problematic for some embodiments of the invention forapplications as a short material working life (pot life) causessignificant difficulties with processing of rapid setting material usingthe equipment and tools involved in actual field application.

Example 1 Comparative Example of Known Geopolymer CementitiousCompositions

The following example illustrates the physical properties of thecomparative cementitious compositions comprising Class C fly ash and analkali metal citrate. The test results show the shrinkage behavior,early age and ultimate compressive strength, and setting behavior of thecementitious compositions shown in TABLE 1. All three mixes wereactivated with potassium citrate and contained varying amounts of sand.All three mixes had about 100 parts by weight Fly Ash Class C and about100 parts by weight Total Cementitious Materials. In other words, allthe cementitious material was Fly Ash Class C.

TABLE 1 Cementitious compositions investigated in Comparative Example 1Comparative Comparative Comparative Raw Material Mix 1 Mix 2 Mix 3 FlyAsh Class C¹ (grams) 3000 2200 1800 Total Cementitious 3000 2200 1800Materials (grams) Sand² (grams) 2250 3300 4500 Water (grams) 825 605 495Potassium Citrate (grams) 120 88 72 Borax (grams) 15 11 9Water/Cementitious 0.275 0.275 0.275 Materials Ratio Sand/Cementitious0.750 1.50 2.50 Materials Ratio Potassium 4.0% 4.0% 4.0%Citrate/Cementitious Materials, wt % Borax Amount/Cementitious 0.5% 0.5%0.5% Materials, wt % ¹Class C Fly Ash, Campbell Power Plant, West Olive,MI ²QUIKRETE Commercial Grade Fine Sand No. 1961

FIG. 1A shows the shrinkage behavior of the cementitious compositionsinvestigated in Comparative Example 1.

The shrinkage measurements were initiated at an age of 4-hours from thetime the raw materials were mixed together and cast. It can be observedthat the fly ash compositions activated with an alkali metal citratedemonstrated extremely high amount of shrinkage. The measured maximumshrinkage was found to be as high as about 0.75% after 8-weeks of curingat about 75° F./50% RH. Increase in sand content decreased the extent ofshrinkage but the overall shrinkage still remained at very high levels.Such high levels of material shrinkage render the material completelyunsatisfactory for most construction applications. It should be notedthat for most construction applications, shrinkage in excess of about0.10% is considered to be high and undesirable.

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 2 shows the initial flow behavior and slump of the cementitiouscompositions investigated in Comparative Example 1.

TABLE 2 Flow and Slump of Cementitious Compositions of ComparativeExample 1 Slump Flow (inches) Comparative Mix 1 (sand/cementitious 10 9material = 0.75) Comparative Mix 2 (sand/cementitious 8 7.5 material =1.5) Comparative Mix 3 (sand/cementitious 2 2 material = 2.5)

The fly ash composition activated with an alkali metal citrate had agood flow behavior at sand/cement ratios of about 0.75. The slurry lostits fluidity to a small extent when the sand/cement ratio was increasedto about 1.5. At a sand/cement ratio of about 2.5, the mix becameextremely stiff and had no flow characteristics.

FIG. 1B shows photograph of slump patty for Mix #1 investigated inComparative Example 1. The slump patty developed significant crackingupon drying. The initiation of cracks in the patties occurred in lessthan about 30 minutes after the slump test. The number of cracks and thesize of cracks grew with subsequent material drying and hardening.

Time of Setting

TABLE 3 shows the setting behavior of the cementitious compositionsinvestigated in Comparative Example 1.

TABLE 3 Setting Times of Cementitious Compositions of ComparativeExample 1 Initial Setting Time Final Setting Time (hr:min) (hr:min)Comparative Mix 1 0:15 0:16 Comparative Mix 2 0:14 0:15 Comparative Mix3 0:7  0:10

The cementitious compositions in this Example had extremely rapidsetting behavior. All mixes gelled up very quickly and lost flowbehavior in less than about 5 minutes after the raw materials wereblended together to form of an aqueous slurry.

Compressive Strength.

TABLE 4 shows the compressive strength behavior of the cementitiouscompositions investigated in Comparative Example 1. All fly ashcompositions showed compressive strength development in excess of about7000 psi at about 28-days.

TABLE 4 Compressive Strength of Cementitious Compositions ComparativeExample 1 28 day (psi) Mix 1 (sand/cementitious material = 0.75) 9259Mix 2 (sand/cementitious material = 1.5) 8069 Mix 3 (sand/cementitiousmaterial = 2.5) 7766

Example 2 Comparative Example

This example investigates early age dimensional stability and crackingresistance of the comparative cementitious compositions comprising flyash and alkali metal citrate. TABLE 5 shows the raw material compositionof the mixture composition investigated. The mixes were activated withsodium citrate and contained varying amounts of sand. The mixes hadabout 100 parts by weight Fly Ash Class C and about 100 parts by weightTotal Cementitious Materials. In other words all the cementitiousmaterial was Fly Ash Class C.

TABLE 5 Mixture Compositions of Comparative Example 2 and ComparativeExample 3 Comparative Comparative Example 2 Example 3 Raw Material Mix 1Mix 1 Fly Ash Class C¹ (grams) 3000 3750 Total Cementitious Materials3000 3750 (grams) Sand² (grams) 3150 3938 Sodium Citrate Dihydrate 60 75(grams) Superplasticizer³ (grams) 15 18.75 Water (grams) 825 1031Water/Cementitious Materials 0.275 0.275 Ratio Sand/CementitiousMaterials 1.05 1.05 Ratio Sodium Citrate 2.0% 2.0%Dihydrate/Cementitious Materials, wt % Superplasticizer/Cementitious0.5% 0.5% Materials, wt % ¹Class C Fly Ash, Campbell Power Plant, WestOlive, MI ²QUIKRETE Commercial Grade Fine Sand No. 1961 ³BASF CASTAMENTFS20

Early Age Cracking Behavior of Material

FIG. 2 shows a photograph of the slump patty for the mix investigated inComparative Example 2. The slump patty developed significant crackingupon drying. The initiation of cracks in the patty occurred in less thanabout 30 minutes after the slump test. The number of cracks and the sizeof cracks grew significantly with subsequent material drying andhardening.

Compressive Strength Behavior of Composition of Comparative Example 2

Table 5A shows the compressive strength behavior of the mix inComparative Example 2. The early age compressive strengths of thecomposition were relatively low, being less than about 500 psi at 4hours and less than about 2000 psi at 24 hours. As will be shown laterin the examples, the geopolymer compositions of embodiments of theinvention develop significantly higher compressive strength at thesesame early ages with equivalent water/cement ratios. As shown in theexamples of specific embodiments of the present invention the early agecompressive strengths of the can easily be tailored by adjusting thetype and amount of calcium sulfate, the amount of calcium sulfoaluminatecement, and the type and amount of alkali metal activator used in thecompositions of embodiments of the invention.

TABLE 5A Compressive Strength of Example 2 - (psi) 4 hour 24 hour 7 day28 day Mix 1 493 1749 6454 8996

Example 3 Comparative Example

This example investigated early age dimensional stability and crackingresistance of the comparative cementitious compositions comprising flyash and alkali metal citrate. TABLE 5 shows the raw material compositionof the mixture composition investigated.

Early Age Cracking Behavior of Material

FIG. 3A shows a photograph of the slump patty for the mix investigatedin the Comparative Example 3. The slump patty developed significantcracking upon drying. The initiation of cracks in the patty occurred inless than about 30 minutes after the slump test.

Compressive Strength Behavior of Composition of Comparative Example 3

Table 5B shows the compressive strength behavior of the mix inComparative Example 3. The early age compressive strengths of thecomposition were relatively low being less than about 500 psi at 4 hoursand less than about 1500 psi. As shown in later examples of embodimentsof the invention, the early age compressive strengths can be tailored byadjusting the type and amount of calcium sulfate, the amount of calciumsulfoaluminate cement, and the type and amount of alkali metal activatorused in the compositions of the invention.

TABLE 5B Compressive Strength of Mixture Compositions of ComparativeExample 3 - (psi) 4 hour 24 hour 7 day 28 day Mix 1 484 1441 6503 8492

Shrinkage Behavior

FIG. 3B shows the very early age shrinkage behavior of the cementitiouscomposition in Comparative Example 3.

The very early age shrinkage measurements were initiated at an age of1-hour from the time the raw materials were mixed together and cast. Thefly ash composition activated with an alkali metal citrate demonstratedextremely high amount of shrinkage. The measured maximum shrinkage wasfound to be in excess of about 1% after 8-weeks of curing at about 75°F./50% RH. Such high levels of material shrinkage render the materialunsatisfactory for most construction applications. In most constructionapplications, shrinkage in excess of about 0.10% is considered to beundesirably high.

Example 4 Addition of Calcium Sulfoaluminate Cement to FlyAsh—Comparative Example

This example shows physical properties of the cementitious compositionscomprising fly ash, calcium sulfoaluminate cement and alkali metalcitrate. This studied the influence of incorporation of calciumsulfoaluminate cement on shrinkage and cracking resistance of thecementitious compositions comprising fly ash and alkali metal citrate.

TABLES 6 and 7 show the raw material compositions of the variouscementitious mixtures 1-4 investigated in this Example. The amount ofcalcium sulfoaluminate cement used in the various mixture compositionswas varied from about 20 wt % to about 80 wt % of the weight of fly ash.

TABLE 6 Comparative Cementitious Reactive Powder Compositions of Example4, Mixes 1 to 4 (Parts by Weight) Mix 1 Mix 2 Mix 3 Mix 4 Parts PartsParts Parts Raw Material by wt. by wt. by wt. by wt. Fly Ash Class C 100100 100 100 Calcium Sulfate 0 0 0 0 Calcium Sulfoaluminate Cement 20 4060 80 Total Cementitious Materials 120 140 160 180 1 Class C Fly Ash,Campbell Power Plant, West Olive, MI 2 FASTROCK 500, CTS Cement Company

TABLE 7 Comparative Cementitious Compositions Mixes 1 to 4 of Example 4Raw Material Mix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 2500 21431875 1667 Calcium Sulfate (grams) 0 0 0 0 Calcium Sulfoaluminate Cement(gms) 500 857 1125 1333 Total Cementitious Materials (grams) 3000 30003000 3000 Sand (grams) 2250 2250 2250 2250 Potassium citrate (grams) 120120 120 120 Superplasticizer (grams) 18 18 18 18 Water (grams) 750 750750 750 Water/Cementitious Materials Ratio 0.25 0.25 0.25 0.25 Sand/Cementitious Materials Ratio 0.75 0.75 0.75 0.75 PotassiumCitrate/Cementitious 4.0% 4.0% 4.0% 4.0% Materials, wt %Superplasticizer/Cementitious 0.6% 0.6% 0.6% 0.6% Materials, wt % 1Class C Fly Ash, Campbell Power Plant, West Olive, MI 2 FASTROCK 500,CTS Cement Company 3 QUIKRETE Commercial Grade Fine Sand No. 1961 4 BASFCASTAMENT FS20

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 8 shows the initial flow behavior and slump of the binary blendsof fly ash and calcium sulfoaluminate cement investigated in Example 4.All mixes investigated had good flow behavior and large patty diameteras observed in the slump test.

TABLE 8 Flow and Slump of Comparative Cementitious Compositions ofExample 4 Flow Slump (inches) Comparative Mix 1 9 9 Comparative Mix 2 1011 Comparative Mix 3 10 10 Comparative Mix 4 10 9.75

FIG. 4A shows a photograph of slump patties for the Mixes 1 and 2investigated in Example 4. FIGS. 4B and 4C show photographs of slumppatties for the Mixes 3 and 4, respectively, investigated in Example 4.All slump patties developed significant cracking upon drying. Theinitiation of cracks in the patties began to occur as soon as about 10minutes after the raw materials were mixed together. The number ofcracks and the size of cracks grew significantly with subsequentmaterial drying and hardening. Mix 1 with lowest amount of calciumsulfoaluminate cement developed the least amount of cracking. Additionof calcium sulfoaluminate cement to fly ash compositions activated withalkali metal citrate led to a dimensionally unstable material prone toexcessive cracking upon drying and hardening.

Shrinkage Behavior

Rectangular prism specimens were cast for characterization of shrinkagebehavior of the mixes investigated. FIG. 4D shows photographs of thespecimens for Mix 1, Mix 2 (samples 2-1 and 2-2), Mix 3 (samples 3-1 and3-2) and Mix 4 (samples 4-1 and 4-2) (left to right) taken about 4 hoursafter they were cast in the mold. FIG. 4D shows that all cast prismspecimen cracked in the mold. All bars shrank extremely significantlyand cracked within couple of hours after the cast in the moldsthemselves (prior to de-molding). Crack widths were measured and thetotal amount of shrinkage for these mixes was determined to be in excessof about 1.0% at the specimen age of about 24 hours.

Example 5

An objective of this investigation was to study the influence ofincorporation of calcium sulfate dihydrate (fine-grained landplaster) atvarying amounts in the geopolymer binder compositions of someembodiments of the invention.

TABLES 9 and 10 show the raw material compositions of the geopolymercementitious mixtures investigated in this Example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisExample was equal to about 40 wt % of the weight of fly ash. Calciumsulfate dihydrate (fine-grained landplaster) was added at differentamount levels (about 25 wt %, about 50 wt %, about 75 wt %, and about100 wt % of the weight of calcium sulfoaluminate cement) in the mixturecompositions investigated. The water/cementitious materials ratioutilized in this example was kept constant at 0.25.

TABLE 9 Example 5 Cementitious reactive powder compositions in parts byweight Mix 1 Mix 2 Mix 3 Mix 4 Parts Parts Parts Parts Raw Material bywt. by wt. by wt. by wt. Fly Ash Class C 100 100 100 100 Calcium SulfateDihydrate 10 20 30 40 Calcium Sulfoaluminate Cement 40 40 40 40 TotalCementitious Materials 150 160 170 180 1 Class C Fly Ash, Campbell PowerPlant, West Olive, MI 2 Landplaster available from USG 3 FASTROCK 500,CTS Company

TABLE 10 Example 5 Compositions Raw Material Mix 1 Mix 2 Mix 3 Mix 4 FlyAsh Class C (grams) 2000 1875 1765 1667 Calcium Sulfate Dihydrate(grams) 200 375 529.4 667 Calcium Sulfoaluminate Cement 800 750 705.9667 (grams) Total Cementitious Materials (grams) 3000 3000 3000 3000Sand (grams) 2250 2250 2250 2250 Potassium Citrate Dihydrate (grams) 120120 120 120 Superplasticizer (grams) 18 18 18 18 Water (grams) 750 750750 750 Water/Cementitious Materials Ratio 0.25 0.25 0.25 0.25Sand/Cementitious Materials Ratio 0.75 0.75 0.75 0.75 CalciumSulfoaluminate Cement/Fly  40%  40%  40%  40% Ash, wt % Calciumsulfate/Calcium  25%  50%  75% 100% Sulfoaluminate Cement, wt %Potassium Citrate/Cementitious 4.0% 4.0% 4.0%  4.0% Materials, wt %Superplasticizer/Cementitious 0.6% 0.6% 0.6%  0.6% Materials, wt % 1Class C Fly Ash, Campbell Power Plant, West Olive, MI 2 Landplasteravailable from USG 3 FASTROCK 500, CTS Company 4 QUIKRETE CommercialGrade Fine Sand No. 1961 5 BASF CASTAMENT FS20

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial.

TABLE 11 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of some embodiments of theinvention comparing fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and an alkali metalcitrate investigated in Example 5. It can be clearly observed that allmixture compositions investigated had good self-leveling and flowbehavior as indicated by the large patty diameter in the slump test. Itis particularly noteworthy that such large slump values andself-leveling behavior was obtainable even at a water/cementitiousmaterials ratio as low as about 0.25.

TABLE 11 Flow and Slump of Example 5 Flow Slump (inches) Mix 1 10 11 Mix2 9 9 Mix 3 8 9 Mix 4 10 9

FIG. 5A shows photographs of slump patties for the geopolymercementitious compositions of some embodiments of the inventioninvestigated in Example 5. The slump patties of this Example did notdevelop any cracking upon drying as it happened for the cementitiousmixtures of Comparative Example 4 containing no calcium sulfatedihydrate (landplaster). Thus, incorporating calcium sulfate dihydrate(fine-grained landplaster) to the cementitious mixture comprising flyash, calcium sulfoaluminate cement, and alkali metal citrate providesdimensionally stable geopolymer cementitious compositions possessingsuperior resistance to cracking.

Shrinkage Behavior

FIG. 5B shows a graph of shrinkage behavior of geopolymer cementitiouscompositions of some embodiments of the invention investigated inExample 5. The main objective of this investigation was to study theinfluence of incorporation of calcium sulfoaluminate cement incombination with a calcium sulfate in the form of fine-grained calciumsulfate dihydrate on shrinkage behavior of the geopolymer cementitiouscompositions of some embodiments of the invention.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following conclusions can be drawn from this investigation and FIG.5B:

Incorporation of calcium sulfate dihydrate (fine-grained landplaster)had a significant impact on improving cracking resistance anddimensional stability of the geopolymer cementitious compositions ofsome embodiments of the invention further comprising fly ash, calciumsulfoaluminate cement and alkali metal citrate. Contrary to theshrinkage bars of comparative Example 4 (with no calcium sulfatedihydrate) which cracked even before de-molding, the shrinkage bars ofExample 5 comprising calcium sulfate dihydrate (fine-grainedlandplaster) were stable and did not evidence cracks indicatingunacceptable dimensional stability or undesirable shrinkage in the barseither prior to or after de-molding.

The measured maximum shrinkage of the geopolymer cementitiouscompositions of some embodiments of the invention comprising fly ash,calcium sulfoaluminate cement, calcium sulfate dihydrate (fine-grainedlandplaster), and alkali metal citrate was significantly lower than thatof the comparative cementitious compositions containing fly ash andalkali metal citrate only (Example 1). For example, the geopolymercementitious compositions of some embodiments of the inventioncomprising fly ash, calcium sulfoaluminate cement, calcium sulfatedihydrate (fine-grained landplaster) and alkali metal citrate hadmaximum measured shrinkage ranging between about 0.07% to about 0.13% incomparison to the maximum shrinkage of about 0.75% for the comparativemixture containing fly ash and alkali metal citrate only (Example 1).Thus, it can be concluded that addition of calcium sulfate dihydrate inthe form of fine-grained landplaster to cementitious compositionscomprising fly ash, calcium sulfoaluminate cement, and alkali metalcitrate helps to very significantly reduce the material shrinkage.

At a low calcium sulfate dihydrate (fine grained landplaster) amount ofabout 25 wt %, the measured maximum shrinkage was about 0.13% after8-weeks of curing at 75° F./50% RH. Further increase in calcium sulfate(fine-grained landplaster) amount in the cementitious compositions ofsome embodiments of the invention decreased the material shrinkage verysignificantly. At a calcium sulfate (fine-grained landplaster) amount ofabout 50 wt %, the measured maximum material shrinkage was reduced toabout 0.08%. Similarly, at a calcium sulfate (fine-grained landplaster)amount of about 75 wt % and about 100 wt %, the measured maximummaterial shrinkage was reduced even further to about 0.07%.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 5C shows a graph of the exothermic and slurry temperature risebehavior of geopolymer cementitious compositions of some embodiments ofthe invention investigated in Example 5. The cementitious compositionsof Example 5 comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citratedemonstrated a very moderate temperature rise behavior. A moderate heatevolution and low temperature rise within the material during the curingstage are effective to prevent excessive thermal expansion andconsequent cracking and disruption of material. This aspect becomes evenmore beneficial when the material is utilized in a manner where largethicknesses of material pours are involved in the actual fieldapplications. The geopolymer cementitious compositions of someembodiments of the invention investigated in this Example are disclosedto be highly beneficial in this particular aspect as they would lead toa lower thermal expansion and enhanced resistance to thermal cracking inactual field applications.

Time of Setting.

TABLE 11 shows a bar chart of the time of setting of geopolymercementitious compositions of some embodiments of the inventioninvestigated in Example 5.

TABLE 11 Setting Times of Example 5 Initial Setting Time (hr:min) FinalSetting Time (hr:min) Mix 1 00:18 00:23 Mix 2 00:20 00:24 Mix 3 00:2400:31 Mix 4 00:25 00:33

All cementitious compositions investigated in Example 5 had rapidsetting behavior with final setting times of about 20 to about 40minutes. The developed cementitious compositions of some embodiments ofthe invention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citratehad relatively longer setting times than the comparative cementitiouscompositions comprising only fly ash and alkali metal citrate as seen inExample 1. For the comparative cementitious composition comprising flyash and alkali metal citrate of Example 1, the time of final setting wasabout 15 minutes. An extremely short setting time is problematic in someembodiments of the inventions for some applications since it provides ashort working life (pot life) that causes significant difficulties withprocessing and placement of rapid setting material in the actual fieldapplications.

In the embodiments of present invention shown in this example it wasunexpectedly found that when the aluminosilicate mineral, alkali metalactivator, calcium sulfoaluminate cement and calcium sulfate were mixedtogether, the resulting reaction was less exothermic than the twoseparate reactions and the time of gelation and hardening times weresignificantly extended.

It has also been found that there is a significant reduction in materialshrinkage when the aluminosilicate mineral and alkali metal activatorwere reacted together with calcium sulfoaluminate cement and calciumsulfate as discussed above in paragraph of the description.

Compressive Strength

TABLE 12 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 5.

TABLE 12 Compressive Strength of Example 5 - (psi) 4 hour 24 hour 8 day28 day Mix 1 1812 3732 5502 6262 Mix 2 2418 4314 6241 5992 Mix 3 31114659 5589 6502 Mix 4 3469 4778 5519 5260

This example studied the influence of incorporation of calciumsulfoaluminate cement in combination with a calcium sulfate in the formof fine-grained landplaster on both the early age and ultimatecompressive strength behavior of the developed geopolymer cementitiouscompositions of some embodiments of the invention. The data indicatesthe following:

The compressive strength of the geopolymer cementitious compositions ofsome embodiments of the invention continued to increase with time.

The early age (about 4-hour and about 24-hour) strength of the mixesincreased with increase in calcium sulfate (landplaster) amount in thecementitious composition.

The early age 4-hour compressive strengths of the material were inexcess of about 1500 psi with the use of calcium sulfate dihydrate inthe form of fine-grained landplaster as a component of the geopolymercementitious compositions of some embodiments of the invention.Moreover, the 4-hour compressive strengths of Mix 3 and Mix 4 containingcalcium sulfate dihydrate in the form of fine-grained landplaster athigher amounts were above about 3000 psi.

The early age i.e. 24-hour compressive strengths of the material were inexcess of about 3500 psi with the use of calcium sulfate in the form offine-grained landplaster as a component of the investigated geopolymercementitious compositions of some embodiments of the invention.Moreover, the 24-hour compressive strengths of Mix 3 and Mix 4containing calcium sulfate (fine-grained landplaster) at higher amountswere above about 4500 psi.

The 28-day compressive strengths of all geopolymer cementitiouscompositions of some embodiments of the invention were very high and inexcess of 5000 psi. The 28-day compressive strengths of Mixes 1 through3 containing were about 6000 psi or greater.

Example 6

An objective of this investigation was to study the influence ofincorporation of calcium sulfate dihydrate (fine-grained landplaster) atvarying amounts in the geopolymer binder compositions of someembodiments of the invention.

TABLE 14 shows the raw material compositions of the geopolymercementitious mixtures investigated in this Example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisExample was equal to 40 wt % of the weight of fly ash. Calcium sulfatedihydrate (finely-grained landplaster) was added at different amountlevels 125 wt %, 150 wt %, 175 wt %, and 200 wt % of the weight ofcalcium sulfoaluminate cement and 50, 60, 70 and 80 wt. % of the flyash, in the various mixture compositions investigated. Thewater/cementitious materials ratio utilized in this example was keptconstant at 0.25. QUIKRETE Commercial Grade Fine Sand No. 1961 and BASFCASTAMENT FS20 superplasticizer were also added.

TABLE 14 Compositions investigated in Example 6 Raw Material Mix 1 Mix 2Mix 3 Mix 4 Fly Ash Class C (grams) 1579 1500 1429 1364 Calcium SulfateDihydrate (grams) 790 900 1000 1091 Calcium Sulfoaluminate Cement 632600 571 546 (grams) Total Cementitious Materials (grams) 3000 2250 30003000 Sand (grams) 2250 3150 2250.0 2250 Potassium Citrate (grams) 120 60120 120 Superplasticizer (grams) 18 18 18 18 Water (grams) 750 750 750750 Water/Cementitious Materials Ratio 0.25 0.25 0.25 0.25Sand/Cementitious Materials Ratio 0.75 0.75 0.75 0.75Superplasticizer/Cementitious  0.6%  0.6%  0.6%  0.6% Materials, wt %Potassium Citrate/Cementitious   4%   4%   4%   4% Materials, wt %Calcium Sulfoaluminate Cement/Fly   40%   40%   40%   40% ash, wt %Calcium Sulfate/Calcium  125%  150%  175%  200% Sulfoaluminate Cement,wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 15 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 6.

TABLE 15 Flow and Slump of Example 6 Flow Slump (inches) Mix 1 8 8.75Mix 2 8 8.5 Mix 3 8 9 Mix 4 8 7

All mixture compositions investigated had good self-leveling, flowbehavior and large patty diameter as observed in the slump test. Thelarge slump and self-leveling behavior was obtainable even at awater/cementitious materials ratio as low as about 0.25.

The slump patties of this Example did not develop any cracking upondrying in contrast to the cementitious mixtures of comparative Example 4containing no calcium sulfate dihydrate (landplaster). Thus, it can beconcluded incorporation of calcium sulfate dihydrate (fine-grainedlandplaster) to the cementitious mixture comprising fly ash, calciumsulfoaluminate cement, and alkali metal citrate provides dimensionallystable geopolymer cementitious compositions possessing superiorresistance to cracking upon drying.

Shrinkage Behavior

FIG. 6A shows shrinkage behavior of geopolymer cementitious compositionsof some embodiments of the invention investigated in Example 6. Theresults from this Example show the synergetic influence of incorporationof calcium sulfoaluminate cement in combination with a fine-grainedcalcium sulfate dihydrate and an alkali metal citrate on shrinkagebehavior of the developed geopolymer cementitious compositions of someembodiments of the invention.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 6A:

The incorporation of calcium sulfate dihydrate in the form offine-grained landplaster had a significant impact on improving thecracking resistance and dimensional stability of geopolymer cementitiouscompositions of some embodiments of the invention comprising fly ash,calcium sulfoaluminate cement and alkali metal citrate. Contrary to theshrinkage bars of comparative Example 4 (with no calcium sulfate) whichcracked even before de-molding, the shrinkage bars of Example 6comprising calcium sulfate dihydrate (fine-grained landplaster) werecompletely stable and did not result in any cracks either prior to orafter de-molding.

The measured maximum shrinkage of the geopolymer cementitiouscompositions of some embodiments of the invention comprising fly ash,calcium sulfoaluminate cement, calcium sulfate dihydrate (fine-grainedlandplaster), and alkali metal citrate was significantly lower than thatof the cementitious compositions comprising fly ash and alkali metalcitrate only (Example 1). For example, the geopolymer cementitiouscompositions of some embodiments of the invention comprising fly ash,calcium sulfoaluminate cement, calcium sulfate dihydrate (fine-grainedlandplaster), and alkali metal citrate had a maximum shrinkage of about0.09% to about 0.12% in comparison to a maximum shrinkage of about 0.75%for the mixture comprising fly ash and alkali metal citrate only(Example 1). Thus, addition of calcium sulfate dihydrate (fine-grainedlandplaster) to cementitious compositions comprising fly ash, calciumsulfoaluminate cement, and alkali metal citrate helps to significantlyreduce the material shrinkage.

Increase in landplaster amount at levels used in this Example resultedin a slight increase in the maximum shrinkage of the material. It can beobserved that at a landplaster amount of about 125 wt %, the materialshrinkage was about 0.09%. Increase in landplaster amount to about 200wt % resulted in increase in the material shrinkage to about 0.12%.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 6B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of some embodiments of theinvention investigated in Example 6. It can be observed that thecementitious compositions of Example 6 comprising fly ash, calciumsulfoaluminate cement, calcium sulfate dihydrate (fine-grainedlandplaster), and alkali metal citrate demonstrated only a very moderatetemperature rise behavior.

A moderate heat evolution and low temperature rise within the materialduring the curing stage are effective to prevent excessive thermalexpansion and consequent cracking and disruption of material. Thisaspect becomes even more beneficial when the material is utilized in amanner where large thicknesses of material pours are involved in theactual field applications. The geopolymer cementitious compositions ofsome embodiments of the invention investigated in this Example aredisclosed to be highly beneficial in this particular aspect as theywould lead to a lower thermal expansion and enhanced resistance tothermal cracking in actual field applications.

Time of Setting

TABLE 16 shows the time of setting of geopolymer cementitiouscompositions of some embodiments of the invention investigated inExample 6 comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citrate.

TABLE 16 Setting Times of Example 6 Initial Setting Final Setting Time(hr:min) Time (hr:min) Mix 1 00:29 00:36 Mix 2 00:31 00:38 Mix 3 00:3300:40 Mix 4 00:30 00:40

All cementitious compositions investigated in this Example showed finalsetting times ranging of about 35 to about 45 minutes. In contrast, thecomparative cementitious composition comprising fly ash and alkali metalcitrate of Example 1 had a very rapid time of final setting of about 15minutes.

Compressive Strength

TABLE 17 shows the early age and ultimate compressive strength behaviorof the developed geopolymer cementitious compositions of someembodiments of the invention comprising fly ash, calcium sulfoaluminatecement, calcium sulfate dihydrate (fine-grained landplaster), and alkalimetal citrate of Example 6.

TABLE 17 Compressive Strength of Example 6 - (psi) 4 hour 24 hour 7 day28 day Mix 1 3149 4843 5691 6090 Mix 2 3410 4667 5967 6546 Mix 3 33244504 5610 6482 Mix 4 2797 4280 5662 5108

The following observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofsome embodiments of the invention investigated in this Example continuedto increase with time.

The early age i.e. 4-hour compressive strengths of the material were inexcess of about 2500 psi with the use of calcium sulfate in the form offine-grained landplaster as a component of the investigated geopolymercementitious compositions of some embodiments of the invention.Moreover, the 4-hour compressive strengths of Mixes 1 through 3 wereabove about 3000 psi.

The early age 24-hour compressive strengths of the material were inexcess of 4000 psi with the use of calcium sulfate in the form offine-grained landplaster as a component of the investigated geopolymercementitious compositions of some embodiments of the invention.

The 28-day compressive strengths of the geopolymer cementitiouscompositions of some embodiments of the invention investigated in thisExample were very high and in excess of 5000 psi. The 28-day compressivestrengths of Mixes 1 through 3 containing calcium sulfate in the form offine-grained landplaster were above 6000 psi.

Example 7

An objective of this investigation was to study the influence ofincorporation of calcium sulfate dihydrate (fine-grained landplaster) atvarying amounts in the geopolymer binder compositions of someembodiments of the invention.

This Example compares comparative Mix 1 without calcium sulfatedihydrate and Mixes 2, 3 and 4 comprising calcium sulfoaluminate cementand a fine-grained calcium sulfate dihydrate.

This Example compares comparative Mix 1 without calcium sulfatedihydrate and Mixes 2, 3 and 4 comprising calcium sulfoaluminate cementand a fine-grained calcium sulfate dihydrate.

TABLE 18 shows the raw material compositions of the geopolymercementitious mixtures investigated in this Example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisExample was equal to 80 wt % of the weight of fly ash. Calcium sulfatedihydrate (fine-grained landplaster) was added at the following amountlevels in the mixture compositions investigated—0 wt %, 10 wt %, 20 wt %and 30 wt % of the weight of calcium sulfoaluminate cement, which is 0,8, 16 and 24 wt. % of the fly ash. The water/cementitious materialsratio utilized in this example was kept constant at 0.30. QUIKRETECommercial Grade Fine Sand No. 1961 and BASF CASTAMENT FS20superplasticizer were also added.

TABLE 18 Example 7 Compositions Mix 1 Raw Material Comparative Mix 2 Mix3 Mix 4 Fly Ash Class C (grams) 1667 1596 1532 1472 Calcium SulfateDihydrate 0.0 128 245 353 (grams) Calcium Sulfoaluminate 1333 1277 12251177 Cement (grams) Total Cementitious Materials 3000 3000 3000 3000(grams) Sand (grams) 3150 3150 3150 3150 Sodium Citrate Dihydrate 60 6060 60 (grams) Superplasticizer (grams) 15 15 15 15 Water (grams) 900 900900 900 Water/Cementitious 0.3 0.3 0.3 0.3 Materials RatioSand/Cementitious 1.05 1.05 1.05 1.05 Materials RatioSuperplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5% Materials, wt % SodiumCitrate/Cementitious 2.0% 2.0% 2.0% 2.0% Materials, wt % CalciumSulfoaluminate  80%  80%  80%  80% cement/Fly ash, wt % CalciumSulfate/Calcium   0%  10%  20%  30% Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 19 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 7.

TABLE 19 Flow and Slump of Example 7 Mix 1 Mix 2 Mix 3 Mix 4 Slump SlumpSlump Slump Flow (inches) Flow (inches) Flow (in.) Flow (in.) 9 10 9 9 88.75 7 8

All mixture compositions investigated had good flow behavior and largepatty diameter as observed in the slump test. The large slump andself-leveling behavior was obtainable even at a water/cementitiousmaterials ratio as low as about 0.3.

FIG. 7A shows the slump patty of comparative Mix 1 of Example 7 whichdid not contain any calcium sulfate dihydrate (fine-grained landplaster)developed significant cracking upon drying. FIG. 7B shows slump pattiesof Mixes 2, 3 and 4 of the geopolymer cementitious compositions of someembodiments of the invention of Example 7 were in excellent conditionand did not develop any cracking.

Shrinkage Behavior

FIG. 7C shows data for shrinkage behavior of geopolymer cementitiouscompositions of some embodiments of the invention investigated in thisExample.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

This investigation showed the following:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate) which cracked even before de-molding, the shrinkage bars ofExample 7 comprising calcium sulfate (fine-grained landplaster) werecompletely stable and did not result in any cracks prior to or afterde-molding.

The geopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citratehad a maximum shrinkage was less than about 0.07% in comparison to amaximum shrinkage of about 0.75% for the comparative mixture compositioncontaining fly ash and alkali metal citrate only (Example 1).

The measured maximum shrinkage of the geopolymer cementitiouscompositions of some embodiments of the invention comprising fly ash,calcium sulfoaluminate cement, calcium sulfate dihydrate (fine-grainedlandplaster), and alkali metal citrate (Mixes 2, 3 and 4) had a maximumshrinkage of less than about 0.07% as compared to the measured maximumshrinkage of about 0.19% of the comparative composition comprising flyash, calcium sulfoaluminate cement and alkali metal citrate only (Mix1).

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 7D shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of some embodiments of theinvention investigated in Example 7. The cementitious compositions ofthis Example comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citratedemonstrated a moderate temperature rise behavior. A moderate heatevolution and low temperature rise within the material during the curingstage are effective to prevent excessive thermal expansion andconsequent cracking and disruption of material. This aspect becomes evenmore beneficial when the material is utilized in a manner where largethicknesses of material pours are involved in the actual fieldapplications. The geopolymer cementitious compositions of someembodiments of the invention investigated in this Example are disclosedto be highly beneficial in this particular aspect as they would lead toa lower thermal expansion and enhanced resistance to thermal cracking inactual field applications.

Time of Setting

TABLE 20 shows the time of setting of geopolymer cementitiouscompositions comparative Mix 1 and inventive Mixes 2, 3 and 4 of Example7.

TABLE 20 Setting Times of Example 7 Initial Setting Final Setting Time(hr:min) Time (hr:min) Mix 1 00:25 1:05 Mix 2 00:26 1:06 Mix 3 00:431:15 Mix 4 00:46 1:20

All the cementitious compositions demonstrated very rapid settingbehavior. However, Mixes 2, 3 and 4 of the present invention comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate dihydrate(fine-grained landplaster), and alkali metal citrate had a relativelylonger setting time than the comparative cementitious compositionscomprising fly ash and alkali metal citrate only (Example 1). The finalsetting times of the geopolymer cementitious composition Mixes 2, 3 and4 of some embodiments of the invention comprising fly ash, calciumsulfoaluminate cement, landplaster, and sodium citrate were about 60 toabout 90 minutes compared to an extremely rapid final setting time ofabout 15 minutes for the comparative mixture composition containing flyash and sodium citrate only (Example 1).

Compressive Strength

TABLE 21 show the compressive strength behavior of the developedgeopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 7.

TABLE 21 Compressive Strength of Example 7 - (psi) 4 hour 24 hour 7 day28 day Mix 1  217  489 1461 4300 Mix 2  597 1848 3408 5976 Mix 3 11942570 4481 5498 Mix 4 1546 2961 4044 6504

The following observations can be drawn:

The compressive strength of the geopolymer cementitious compositions ofsome embodiments of the invention investigated in this Example continuedto increase with time.

Both the early age compressive strength and the ultimate compressivestrength of the comparative mixture composition without calcium sulfate(Mix 1) were lower in comparison to those for the cementitiouscompositions of some embodiments of the invention comprising landplaster(Mixes 2 through 4).

The early age (4-hour and 24-hour) compressive strength of thegeopolymer cementitious compositions of some embodiments of theinvention increased with increase in the amount of calcium sulfatedihydrate (fine-grained landplaster) in the material.

The early age 24-hour compressive strength of the material was in excessof about 1500 psi with the use of calcium sulfate dihydrate(fine-grained landplaster) as a component of the geopolymer cementitiouscompositions of some embodiments of the invention. The 24-hourcompressive strengths of the Mixes 3 and 4 were in excess of about 2500psi.

The 28-day compressive strength of all geopolymer cementitiouscompositions of some embodiments of the invention comprising fly ash,calcium sulfoaluminate, landplaster and sodium citrate was very high andin excess of about 5000 psi. The 28-day compressive strength of Mix 4comprising landplaster at an amount of about 30 wt % (of the weight ofcalcium sulfoaluminate cement) was in excess of about 6000 psi.

Example 8

An objective of this investigation was to study the influence ofincorporation of calcium sulfate dihydrate (fine-grained landplaster) atvarying amounts in the geopolymer binder compositions of someembodiments of the invention.

This Example depicts physical properties of the developed geopolymercementitious compositions of some embodiments of the inventioncomprising fly ash, calcium sulfoaluminate cement, fine-grained calciumsulfate dihydrate (i.e., gypsum or landplaster) and alkali metalcitrate. TABLES 22 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisExample was equal to about 80 wt % of the weight of fly ash. Landplasterwas added at the following amounts in the mixture compositionsinvestigated—40 wt %, 50 wt %, 60 wt % and 80 wt % of the weight ofcalcium sulfoaluminate cement, which is 32, 40, 48 and 64 wt % of thefly ash. The water/cementitious materials ratio utilized in this examplewas kept constant at 0.30. QUIKRETE Commercial Grade Fine Sand No. 1961and BASF CASTAMENT FS20 superplasticizer were added.

TABLE 22 Geopolymer compositions of Example 8 Raw Material Mix 1 Mix 2Mix 3 Mix 4 Fly Ash Class C (grams) 1415 1364 1316 1230 Calcium SulfateDihydrate 453 546 632 787 (grams) Calcium Sulfoaluminate Cement 11321091 1053 984 (grams) Total Cementitious Materials 3000 3000 3000 3000(grams) Sand (grams) 3150 3150 3150 3150 Sodium Citrate Dihydrate(grams) 60 60 60 60 Superplasticizer (grams) 15 15 15 15 Water (grams)900 900 900 900 Water/Cementitious Materials 0.3 0.3 0.3 0.3 RatioSand/Cementitious Materials 1.05 1.05 1.05 1.05 RatioSuperplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5% Materials, wt % SodiumCitrate/Cementitious 2.0% 2.0% 2.0% 2.0% Materials, wt % CalciumSulfoaluminate  80%  80%  80%  80% cement/Fly ash, wt % CalciumSulfate/Calcium  40%  50%  60%  80% Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 23 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 8.

TABLE 23 Flow and Slump of Example 8 Flow Slump (inches) Mix 1 8 8.5 Mix2 8 8.5 Mix 3 8 8 Mix 4 8 8

All mixture compositions investigated had good self-leveling, flowbehavior and large patty diameter as observed in the slump test. It isparticularly noteworthy that such large slump and self-leveling behaviorwas obtainable even at a water/cementitious materials ratio as low asabout 0.3.

The slump patties for all four mixes comprising calcium sulfatedihydrate (fine-grained landplaster) were in excellent condition anddeveloped no cracking.

Shrinkage Behavior

FIG. 8A shows shrinkage behavior of the geopolymer cementitiouscompositions of some embodiments of the invention investigated inExample 8. The shrinkage measurements were initiated at an age of about4-hours from the time the raw materials were mixed together to form anaqueous slurry. The material shrinkage was measured for a total durationof about 8-weeks while curing the material at about 75° F./50% RelativeHumidity (RH).

The following important conclusions can be drawn from this investigationand FIG. 8A:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate) which cracked even before de-molding, the shrinkage bars ofExample 8 comprising calcium sulfate dihydrate (fine-grainedlandplaster) were completely stable and did not result in any crackseither prior to or after de-molding.

The geopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citratehad a maximum shrinkage of about 0.07% to about 0.18% in comparison to amaximum shrinkage of about 0.75% for the comparative mixture compositioncontaining fly ash and alkali metal citrate only (Example 1).

Increase in calcium sulfate dihydrate (fine-grained landplaster) amountbeyond a certain level had an effect of increasing the materialshrinkage. For instance, at a landplaster amount of about 40 wt % (Mix1), the total shrinkage was about 0.07%, at a landplaster amount ofabout 60 wt % (Mix 3), the total shrinkage had increased to a value ofabout 0.13%, and at a landplaster amount of about 80 wt % (Mix 4), thetotal shrinkage had increased further to a value of about 0.18%.

Comparing the shrinkage testing results from Example 7 and Example 8,there is a preferred calcium sulfate dihydrate (fine-grainedlandplaster) amount range that provides minimal material shrinkage. Thisamount range of calcium sulfate dihydrate (fine-grained landplaster)appears to be about 10 to about 50 wt. % of the weight of calciumsulfoaluminate cement for the investigated cementitious compositions inthese examples.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 8B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of some embodiments of theinvention investigated in Example 8. The cementitious compositions ofthis Example comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citratedemonstrated only a very moderate temperature rise behavior. Thisprevents excessive thermal expansion and consequent cracking anddisruption of material. This aspect becomes even more beneficial whenthe material is utilized in a manner where large thicknesses of materialpours are involved in the actual field applications. The geopolymercementitious compositions of some embodiments of the inventioninvestigated in this Example are disclosed to be highly beneficial inthis particular aspect as they would lead to a lower thermal expansionand enhanced resistance to thermal cracking in actual fieldapplications.

Time of Setting

TABLE 24 shows the time of setting of geopolymer cementitiouscompositions of some embodiments of the invention investigated inExample 8.

TABLE 24 Setting Times of Example 7 Initial Setting Final Setting Time(hr:min) Time (hr:min) Mix 1 00:44 1:18 Mix 2 00:45 1:22 Mix 3 00:521:22 Mix 4  1:02 1:34

All cementitious compositions investigated in this Example demonstratedvery rapid setting behavior. Also, the final setting times of thegeopolymer cementitious compositions of some embodiments of theinvention of this Example comprising fly ash, calcium sulfoaluminatecement, calcium sulfate dihydrate (landplaster), and sodium citrate wereabout 60 to about 90 minutes compared to an extremely rapid finalsetting time of about 15 minutes for the comparative mixture compositioncontaining fly ash and sodium citrate only (Example 1).

Compressive Strength

TABLE 25 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 8.

TABLE 25 Compressive Strength of Example 8 (psi) 4 hour 24 hour 7 day 28day Mix 1 1619 4118 4561 6892 Mix 2 1776 4336 4603 6148 Mix 3 1752 44175132 7099 Mix 4 1458 3277 3714 4678

The example studied the influence of incorporation of calciumsulfoaluminate cement in combination with calcium sulfate (fine-grainedlandplaster) and an alkali metal citrate on both the early age andultimate compressive strength behavior of the developed geopolymercementitious compositions of some embodiments of the invention. Thefollowing observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofsome embodiments of the invention investigated in this Example continuedto increase with time.

Both the early age compressive strength and the ultimate compressivestrength of the mixture composition without calcium sulfate (Mix 1 ofExample 7) were lower in comparison to those for the cementitiouscompositions of some embodiments of the invention comprising calciumsulfate (fine-grained landplaster) (Mixes 1 through 4).

Comparing the testing results for Example 7 and Example 8, it can beobserved that the early age (4-hour and 24-hour) compressive strength ofthe geopolymer cementitious compositions of some embodiments of theinvention increased with increase in the amount of calcium sulfate(fine-grained landplaster) in the material.

The early age (4-hour and 24-hour) compressive strengths of geopolymercementitious compositions of some embodiments of the invention at highamounts of calcium sulfate (fine-grained landplaster) were very high.The mixture compositions comprising calcium sulfate (fine-grainedlandplaster) at amount levels equal to about 40 wt %, about 50 wt % andabout 60 wt %, had respective about 4-hour compressive strengths inexcess of about 1500 psi and the respective about 24-hour compressivestrength were in excess of about 4000 psi.

The early age 4-hour and 24-hour compressive strength show someembodiments of the invention are capable of developing significantlygreater early age compressive strengths when compared to the 4 hour and24 hour compressive strength of about 500 psi and 2000 psi shown incomparative examples 2 and 3.

The 28-day compressive strengths of all geopolymer cementitiouscompositions of some embodiments of the invention comprising fly ash,calcium sulfoaluminate, calcium sulfate dihydrate (landplaster) andsodium citrate were very high and in excess of about 4500 psi. Thecementitious compositions of some embodiments of the inventioncomprising calcium sulfate dihydrate (fine-grained landplaster) atamount levels equal to about 40 wt %, about 50 wt % and about 60 wt %,had respective 28-day compressive strength in excess of about 6000 psi.

Example 9

An objective of this investigation was to study the influence ofincorporation of calcium sulfate dihydrate (fine-grained landplaster) atvarying amounts in the geopolymer binder compositions of someembodiments of the invention.

TABLE 26 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example.

The amount of calcium sulfoaluminate cement used in the mixturecompositions of this Example was equal to 80 wt % of the weight of flyash. Calcium sulfate dihydrate in the form of fine-grained landplasterwas added at the following amount levels in the mixture compositionsinvestigated—0 wt %, 10 wt %, 20 wt % and 30 wt % of the weight ofcalcium sulfoaluminate cement, which is 0, 8, 16 and 24 wt. % of the flyash. The water to cementitious materials ratio utilized in this examplewas kept constant at 0.25.

TABLE 26 Compositions investigated in Example 9 Comparative Raw MaterialMix #1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 1667 1596 1531 1471Calcium Sulfate Dihydrate 0 128 245 353 (grams) Calcium Sulfoaluminate1333 1277 1225 1177 Cement (grams) Total Cementitious Materials 30003000 3000 3000 (grams) Sand (grams) 3150 3150 3150 3150 Sodium CitrateDihydrate 60 60 60 60 Superplasticizer (grams) 15 15 15 15 Water (grams)750 750 750 750 Water/Cementitious Materials 0.25 0.25 0.25 0.25 RatioSand/Cementitious Materials 1.05 1.05 1.05 1.05 RatioSuperplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5% Materials, wt % SodiumCitrate/Cementitious   2%   2%   2%   2% Materials, wt % CalciumSulfoaluminate  80%  80%  80%  80% cement/Fly ash, wt % CalciumSulfate/Calcium   0%  10%  20%  30% Sulfoaluminate Cement, wt %

Slump and Early Age Cracking Behavior of Material

TABLE 27 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 9.

TABLE 27 Flow and Slump of Example 9 Flow Slump (inches) Mix 1 7 9 Mix 26 7 Mix 3 5 6.5 Mix 4 5 6

All mixture compositions investigated had good rheology and slumpbehavior as observed in the slump test. It is particularly noteworthythat such good rheology and slump behavior was obtainable even at awater/cementitious materials ratio as low as about 0.25.

All mixes containing calcium sulfate dihydrate (fine-grainedlandplaster) were in excellent condition and did not develop anycracking.

Shrinkage Behavior

FIG. 9A shows shrinkage behavior of geopolymer cementitious compositionsof some embodiments of the invention investigated in Example 9. The mainobjective of this investigation was to study the influence ofincorporation of calcium sulfoaluminate cement in combination with afine-grained calcium sulfate dihydrate (landplaster) and an alkali metalcitrate on shrinkage behavior of the developed geopolymer cementitiouscompositions of some embodiments of the invention.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following conclusions can be drawn from this investigation and FIG.9A:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate) which cracked before de-molding, the shrinkage bars of Example9 comprising calcium sulfate dihydrate (fine-grained landplaster) werestable and did not crack, either prior to or after de-molding.

The geopolymer cementitious compositions of some embodiments of theinvention (Example 9) comprising fly ash, calcium sulfoaluminate cement,calcium sulfate dihydrate (fine-grained landplaster), and alkali metalcitrate had a maximum shrinkage less than about 0.07% in comparison to amaximum shrinkage of about 0.75% for the comparative mixture compositioncontaining fly ash and alkali metal citrate only (Example 1).

The mixture compositions comprising fly ash, calcium sulfoaluminatecement, calcium sulfate (fine-grained landplaster), and alkali metalcitrate (Mixes 2, 3 and 4) had a maximum shrinkage of less than about0.07%, while the maximum shrinkage of comparative Mix 1 comprising flyash, calcium sulfoaluminate cement, alkali metal citrate but no calciumsulfate (landplaster) was very high at about 0.17%.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 9B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of some embodiments of theinvention investigated in Example 9. The cementitious compositions ofthis Example comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citratedemonstrated only a very moderate temperature rise behavior. Also,decreasing the water to cementitious materials ratio from about 0.30 toabout 0.25 (comparing results from Examples 7 and 9), did not change thetemperature rise behavior to any significant degree.

A moderate heat evolution and low temperature rise within the materialduring the curing stage are significant in assisting to preventexcessive thermal expansion and consequent cracking and disruption ofmaterial. This aspect becomes even more helpful when the material isutilized in a manner where large thicknesses of material pours areinvolved in the actual field applications. The geopolymer cementitiouscompositions of some embodiments of the invention investigated in thisExample are disclosed to be highly beneficial in this particular aspectas they would lead to a lower thermal expansion and enhanced resistanceto thermal cracking in actual field applications.

Time of Setting

TABLE 28 shows the time of setting of geopolymer cementitiouscompositions of some embodiments of the invention investigated inExample 9.

TABLE 28 Setting Times of Example 9 Initial Setting Final Setting Time(hr:min) Time (hr:min) Mix 1 00:19 00:30 Mix 2 00:20 00:45 Mix 3 00:2500:48 Mix 4 00:25 00:50

All cementitious compositions investigated in this Example had rapidsetting behavior. The final setting times of the geopolymer cementitiouscompositions of some embodiments of the invention of this Examplecomprising fly ash, calcium sulfoaluminate cement, calcium sulfatedihydrate (fine-grained landplaster), and sodium citrate were over about45 minutes compared to an extremely rapid final setting time of about 15minutes for the comparative mixture composition containing fly ash andsodium citrate only (Example 1). Comparative Mix #1 without calciumsulfate (landplaster) had significantly shorter setting time compared tothe Mixes 2 through 4 of some embodiments of the invention containingcalcium sulfate dihydrate (landplaster). An extremely short setting timeis problematic for some embodiments of the invention.

Compressive Strength

TABLE 29 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 9.

TABLE 29 Compressive Strength of Example 9 (psi) 4 hour 24 hour 7 day 28day Mix 1 378 953 2404 4694 Mix 2 1063 2773 5493 6678 Mix 3 1758 36985346 7437 Mix 4 2241 4221 5895 7697

The following observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofsome embodiments of the invention in this Example continued to increasewith time.

Both the early age compressive strength and the ultimate compressivestrength of the mixture composition without landplaster (Mix 1) werelower in comparison to those for the cementitious compositions of someembodiments of the invention comprising landplaster (Mixes 2 through 4).

The early age (4-hour and 24-hour) compressive strength of thegeopolymer cementitious compositions of some embodiments of theinvention increased with increase in the amount of calcium sulfate(fine-grained landplaster) in the material.

The 4-hour compressive strengths of material were in excess of about1000 psi with the use of calcium sulfate (fine-grained landplaster) inthe geopolymer cementitious compositions of some embodiments of theinvention investigated in this example. Moreover, the 4-hour compressivestrengths of Mix 3 and Mix 4 comprising calcium sulfate (fine-grainedlandplaster) were in excess of about 1500 psi and about 2000 psi,respectively. In contrast, in absence of calcium sulfate dihydrate(landplaster), the about 4-hour compressive strength of the material wasrelatively very low being less than about 400 psi (Mix 1).

The 24-hour compressive strengths of material were in excess of about2500 psi with the use of calcium sulfate dihydrate (fine-grainedlandplaster) in the geopolymer cementitious compositions of someembodiments of the invention investigated in this example. Moreover, theabout 24-hour compressive strengths of Mix 3 and Mix 4 comprisingcalcium sulfate dihydrate (fine-grained landplaster) were in excess ofabout 3500 psi. In contrast, in absence of landplaster, the about24-hour compressive strength of the material was less than about 1000psi (Mix 1).

The early age 4-hour and 24-hour compressive strength show someembodiments of the invention are capable of developing significantlygreater early age compressive strengths when compared to the 4 hour and24 hour compressive strength of about 500 psi and 2000 psi shown incomparative examples 2 and 3.

The 28-day compressive strength of all geopolymer cementitiouscompositions of some embodiments of the invention comprising fly ash,calcium sulfoaluminate, calcium sulfate dihydrate (landplaster) andsodium citrate was very high and in excess of about 6000 psi.

Example 10

An objective of this investigation was to study the influence ofincorporation of calcium sulfate dihydrate (fine-grained landplaster) atvarying amounts in the geopolymer binder compositions of someembodiments of the invention.

TABLE 30 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisExample was equal to 80 wt % of the weight of fly ash. Calcium sulfatedihydrate in the form of fine-grained landplaster was added at thefollowing amount levels in the mixture compositions investigated—40 wt%, 50 wt %, 60 wt % and 80 wt % of the weight of calcium sulfoaluminatecement. The calcium sulfate dihydrate is 32, 40, 48 and 64 wt. % of thefly ash. The water to cementitious materials ratio utilized in thisexample was kept constant at 0.25. The sand used is QUIKRETE CommercialGrade Fine Sand No. 1961 and the Superplasticizer is BASF CASTAMENTFS20.

TABLE 30 Compositions of Example 10 Raw Material Mix 1 Mix 2 Mix 3 Mix 4Fly Ash Class C (grams) 1415 1364 1316 1230 Calcium Sulfate Dihydrate(grams) 453 546 632 787 Calcium Sulfoaluminate Cement 1132 1091 1053 984(grams) Total Cementitious Materials 3000 3000 3000 3000 (grams) Sand(grams) 3150 3150 3150 3150 Sodium Citrate Dihydrate (grams) 60 60 60 60Superplasticizer (grams) 15 15 15 15 Water (grams) 750 750 750 750Water/Cementitious Materials 0.25 0.25 0.25 0.25 Ratio Sand/Cementitious Materials 1.05 1.05 1.05 1.05 RatioSuperplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5% Materials, wt % SodiumCitrate/Cementitious 2.0% 2.0% 2.0% 2.0% Materials, wt % CalciumSulfoaluminate 80% 80% 80% 80% cement/Fly ash, wt % CalciumSulfate/Calcium 40% 50% 60% 80% Sulfoaluminate Cement, wt %

Slump and Early Age Cracking Behavior of Material

TABLE 31 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 10.

TABLE 31 Flow and Slump of Example 10 Flow Slump (inches) Mix 1 6 6.25Mix 2 5 6 Mix 3 5 6 Mix 4 5 6

All mixture compositions investigated had good rheology and slumpbehavior as observed in the slump test. It is particularly noteworthythat such good rheology and slump behavior was obtainable even at awater/cementitious materials ratio as low as about 0.25.

All mixes containing calcium sulfate dihydrate (fine-grainedlandplaster) were in excellent condition and did not develop anycracking.

Shrinkage Behavior

FIG. 10A shows shrinkage behavior of geopolymer cementitiouscompositions of some embodiments of the invention investigated inExample 10.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 10A:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate) which cracked even before de-molding, the shrinkage bars ofExample 10 comprising calcium sulfate dihydrate (fine-grainedlandplaster) were completely stable and did not result in any crackseither prior to or after de-molding.

The geopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citratehad a maximum shrinkage between about 0.08% to about 0.14% in comparisonto a maximum shrinkage of about 0.75% for the comparative mixturecomposition containing fly ash and alkali metal citrate only (Example1).

The mixture compositions comprising fly ash, calcium sulfoaluminatecement, calcium sulfate dihydrate (fine-grained landplaster), and alkalimetal citrate had a maximum shrinkage between about 0.08% and about0.14%. In contrast, the maximum shrinkage of Comparative Mix 1 ofExample 9 comprising fly ash, calcium sulfoaluminate cement, alkalimetal citrate but no calcium sulfate dihydrate (landplaster) was about0.17%.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 10B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of some embodiments of theinvention investigated in Example 10. The cementitious compositions ofthis Example comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citratedemonstrated only a very moderate temperature rise behavior. Also,decreasing the water to cementitious materials ratio from about 0.30 toabout 0.25 (comparing results from Examples 8 and 10), did not changethe temperature rise behavior to any significant degree.

A moderate heat evolution and low temperature rise within the materialduring the curing stage assists in preventing excessive thermalexpansion and consequent cracking and disruption of material. Thisaspect becomes even more helpful when the material is utilized in amanner where large thicknesses of material pours are involved in theactual field applications. The geopolymer cementitious compositions ofsome embodiments of the invention investigated in this Example aredisclosed to be highly beneficial in this particular aspect as theywould lead to a lower thermal expansion and enhanced resistance tothermal cracking in actual field applications.

Time of Setting

TABLE 32 shows the time of setting of geopolymer cementitiouscompositions of some embodiments of the invention investigated inExample 10.

TABLE 32 Setting Times of Example 10 Initial Setting Time (hr:min) FinalSetting Time (hr:min) Mix 1 00:31 00:51 Mix 2 00:33 00:56 Mix 3 00:3400:57 Mix 4 00:35  1:02

All cementitious compositions investigated in this Example had rapidsetting behavior. The final setting times of the geopolymer cementitiouscompositions of some embodiments of the invention of this Examplecomprising fly ash, calcium sulfoaluminate cement, landplaster, andsodium citrate were over about 50 minutes compared to an extremely rapidfinal setting time of about 15 minutes for the comparative mixturecomposition containing fly ash and sodium citrate only (Example 1).Also, the Comparative Mix 1 of Example 9 without landplaster hadsignificantly shorter set compared to the Mixes 1 through 4 of Example10 containing landplaster.

Compressive Strength

TABLE 33 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of some embodiments of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate (fine-grained landplaster), and alkali metal citrateinvestigated in Example 10.

TABLE 33 Compressive Strength of Example 10 - (psi) 4 hour 24 hour 7 day28 day Mix 1 2528 4894 6232 6985 Mix 2 2381 4405 5742 7167 Mix 3 23404367 5741 7117 Mix 4 2075 4840 5602 7812

The following important observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofsome embodiments of the invention investigated in this Example continuedto increase with time.

The early age (4-hour and 24-hour) compressive strength of thegeopolymer cementitious compositions of some embodiments of theinvention increased with increase in the amount of calcium sulfate(fine-grained landplaster) in the material.

The 4-hour compressive strengths of material were in excess of about2000 psi with the use of calcium sulfate dihydrate (fine-grainedlandplaster) in all four geopolymer cementitious compositions of someembodiments of the invention investigated in this example. In fact, theabout 4-hour compressive strengths of the Mixes #1 through #3 comprisingcalcium sulfate dihydrate (fine-grained landplaster) were in excess ofabout 2500 psi. On the other hand, in absence of landplaster, the about4-hour compressive strength of the material was relatively very lowbeing less than about 400 psi (Comparative Mix #1 of Example 9).

The 24-hour compressive strengths of material were in excess of about4000 psi with the use of calcium sulfate dihydrate (fine-grainedlandplaster) in all four geopolymer cementitious compositions of someembodiments of the invention investigated in this example. On the otherhand, in absence of calcium sulfate dihydrate (landplaster), the about24-hour compressive strength of the material was relatively very lowbeing less than about 1000 psi (Comparative Mix #1 of Example 9).

The 28-day compressive strength of all geopolymer cementitiouscompositions of some embodiments of the invention comprising fly ash,calcium sulfoaluminate, calcium sulfate (landplaster) and sodium citratewas again very high and in excess of about 7000 psi.

Example 11

An objective of this investigation was to study the influence ofincorporation of alkali metal citrate at varying amounts in thegeopolymer binder compositions of this embodiment.

TABLE 34 shows the raw material compositions of the geopolymercementitious mixtures investigated in the Example 11.

The amount of calcium sulfoaluminate cement used in the mixturecompositions of this Example was equal to 80 wt % of the weight of flyash. Calcium sulfate dihydrate in the form of fine-grained landplasterwas added at an amount equal to 30 wt % of the weight of calciumsulfoaluminate cement. Calcium sulfate dihydrate is used at 24 wt % ofthe fly ash. Alkali metal citrate in the form of sodium citrate wasadded at the following amount levels in the cementitious compositionsinvestigated—2.00 wt %, 1.25 wt %, 0.50 wt % and 0.00 wt % of the weightof the total cementitious materials. The water to cementitious materialsratio utilized in this investigation was kept constant at 0.275. Thesand QUIKRETE Commercial Grade Fine Sand No. 1961 and the plasticizer isBASF CASTAMENT FS20.

TABLE 34 Compositions of Example 11 Raw Material Mix 1 Mix 2 Mix 3 Mix 4Fly Ash Class C (grams) 1593 1593 1593 1593 Calcium Sulfate Dihydrate(grams) 382 382 382 382 Calcium Sulfoaluminate Cement 1275 1275 12751275 (grams) Total Cementitious Materials 3250 3250 3250 3250 (grams)Sand (grams) 3413 3413 3413 3413 Sodium Citrate Dihydrate (grams) 6540.63 16.25 0 Superplasticizer (grams) 16.25 16.25 16.25 16.25 Water(grams) 894 894 894 894 Water/Cementitious Materials 0.275 0.275 0.2750.275 Ratio Sand/ Cementitious Materials 1.05 1.05 1.05 1.05 RatioSuperplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5% Materials, wt % SodiumCitrate/Cementitious 2% 1.25% 0.5% 0% Materials, wt % CalciumSulfoaluminate 80% 80% 80% 80% cement/Fly ash, wt % CalciumSulfate/Calcium 30% 30% 30% 30% Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 35 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate (fine-grainedlandplaster), and different amounts of alkali metal citrate investigatedin Example 11.

TABLE 35 Flow and Slump of Example 11 Flow Slump (inches) Mix 1 9 8.75Mix 2 9 9.5 Mix 3 9 9.0 Mix 4 10 10.5

All mixture compositions investigated had good flow behavior and largepatty diameter as observed in the slump test. It is noteworthy that suchlarge slump and self-leveling behavior was obtained even when thewater/cementitious materials ratio was as low as about 0.275.

FIG. 11A shows photographs of slump patties for the cementitious mixturecompositions investigated in Example 11. The slump patty for Mix 1 atabout 2% sodium citrate was free of cracks that would indicatedimensional instability or unacceptable shrinkage. On the other hand,the slump patties for Mixes 2, 3, and 4 containing about 1.25%, 0.5% and0% sodium citrate, respectively, developed several microcracks upondrying. Thus, this experiment shows decreasing the amount of alkalimetal citrate in the composition below a certain amount can increase thecracking potential of the geopolymer cementitious compositionscomprising fly ash, calcium sulfoaluminate and landplaster.

Shrinkage Behavior

FIG. 11B shows shrinkage behavior of geopolymer cementitiouscompositions of the embodiment investigated in Example 11. The mainobjective of this investigation was to study the influence of varyingamounts of alkali metal citrate on shrinkage behavior of the developedgeopolymer cementitious compositions of this embodiment.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 11B. The measured maximum shrinkage was lowest, about 0.06%, ata sodium citrate amount of about 2.0%. Decreasing the sodium citrateamount increased the maximum shrinkage of the material. For example, ata sodium citrate amount of about 1.25%, the measured maximum shrinkagewas about 0.14%, while at a sodium citrate amount of about 0.5%, themeasured maximum shrinkage increased to about 0.23%.

The geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate dihydrate(fine-grained landplaster), and alkali metal citrate had a maximumshrinkage of about 0.06% to about 0.24% in comparison to a maximumshrinkage of about 0.75% for the comparative mixture compositioncontaining fly ash and alkali metal citrate only (Example 1).

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 11C shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of this embodiment investigated inExample 11. The cementitious compositions of this Example comprising flyash, calcium sulfoaluminate cement, calcium sulfate dihydrate(fine-grained landplaster), and alkali metal citrate demonstrated only avery moderate temperature rise behavior. A moderate heat evolution andlow temperature rise within the material during the curing stage issignificant in preventing excessive thermal expansion and consequentcracking and disruption of material. This aspect becomes even morehelpful when the material is utilized in a manner where largethicknesses of material pours are involved in the actual fieldapplications. The geopolymer cementitious compositions of the embodimentinvestigated in this Example are disclosed to be highly beneficial inthis particular aspect as they would lead to a lower thermal expansionand enhanced resistance to thermal cracking in actual fieldapplications.

Time of Setting

TABLE 36 shows the time of setting of geopolymer cementitiouscompositions of the embodiment of Example 11.

TABLE 36 Setting Times of Example 11 Initial Setting Time (hr:min) FinalSetting Time (hr:min) Mix 1 00:38 1:09 Mix 2 00:59 1:30 Mix 3  1:15 2:20Mix 4  1:20 2:25

All cementitious compositions in this Example demonstrated very rapidsetting behavior. The time of final setting reduced with increase in theamount of sodium citrate. For instance, the mixture compositionscontaining about 0% and about 0.5% sodium citrate (Mix 4 and Mix 3) hada final setting time of about 2 hours, while the mixture compositioncontaining about 2.0% sodium citrate achieved a final setting time ofabout 1 hour only.

Example 12

An objective of this investigation was to study the influence ofincorporation of alkali metal citrate at various amounts in thegeopolymer binder compositions of this embodiment.

TABLE 37 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example.

The amount of calcium sulfoaluminate cement used in the mixturecompositions of this Example was equal to 80 wt % of the weight of flyash. Calcium sulfate dihydrate in the form of fine-grained landplasterwas added at an amount equal to 30 wt % of the weight of calciumsulfoaluminate cement and 24 wt % of the fly ash. Sodium citrate wasadded at the following amounts in the cementitious compositionsinvestigated—2.00 wt %, 3.00 wt %, 4.00 wt % and 5.00 wt % of the weightof the total cementitious materials. The sand is QUIKRETE CommercialGrade Fine Sand No. 1961 and the superplasticizer is BASF CASTAMENT FS20

TABLE 37 Geopolymer cementitious compositions of Example 12 Raw MaterialMix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 1593 1593 1593 1593Calcium Sulfate Dihydrate 382 382 382 382 (grams) Calcium SulfoaluminateCement 1275 1275 1275 1275 (grams) Total Cementitious Materials 32503250 3250 3250 (grams) Sand (grams) 3413 3413 3413 3413 Sodium CitrateDihydrate (grams) 65 98 130 163 Superplasticizer (grams) 16.25 16.2516.25 16.25 Water (grams) 893 893 893 893 Water/Cementitious Materials0.275 0.275 0.275 0.275 Ratio Sand/ Cementitious Materials 1.05 1.051.05 1.05 Ratio Superplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5%Materials, wt % Sodium Citrate/Cementitious 2% 3% 4% 5% Materials, wt %Calcium Sulfoaluminate 80% 80% 80% 80% cement/Fly ash, wt % CalciumSulfate/Calcium 30% 30% 30% 30% Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 38 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate dihydrate(fine-grained landplaster), and different amounts of alkali metalcitrate investigated in Example 12.

TABLE 38 Flow and Slump of Example 12 Flow Slump (inches) Mix 1 9 8.75Mix 2 9 9 Mix 3 10 10 Mix 4 10 10

All mixture compositions investigated had good self-leveling, flowbehavior and large patty diameter as observed in the slump test evenwhen the water/cementitious materials ratio was as low as about 0.275.

All the slump patties for the mixes investigated in Example 12 led togood flow behavior. Further, all four mixture compositions containingdifferent amounts of sodium citrate led to slump patties that were freeof cracks. This is in contrast to some of the slump patties of Example11 that developed cracking at lower amounts of sodium citrate.

Shrinkage Behavior

FIG. 12A shows shrinkage behavior of geopolymer cementitiouscompositions of the embodiment investigated in Example 12.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following conclusions can be drawn from this Example and FIG. 12A:The measured total shrinkage was lowest, about 0.06%, at a sodiumcitrate amount of about 2% and about 3%. Increasing the sodium citrateamount increased the maximum shrinkage of the material. For example, ata sodium citrate amount of about 3%, the measured maximum shrinkage wasabout 0.14%, while at a sodium citrate amount of about 4%, the measuredmaximum shrinkage increased to about 0.23%.

Comparison of the shrinkage testing results for Example 11 and Example12 shows there exists, in one embodiment, a preferred amount range ofalkali metal citrate at which the material shrinkage of the geopolymercementitious compositions of this embodiment comprising fly ash, calciumsulfoaluminate and calcium sulfate is minimal. This preferred amount ofalkali metal citrate in this embodiment is from about 1% to about 4%,and more preferably from about 2% to about 3%.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 12A shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of the embodiment investigated inExample 12. The cementitious compositions of this Example comprising flyash, calcium sulfoaluminate cement, calcium sulfate dihydrate(fine-grained landplaster), and alkali metal citrate demonstrated verymoderate temperature rise behavior. Increase in the amount of sodiumcitrate increased the maximum temperature rise but overall increase wasvery small and not significant. In this embodiment, a moderate heatevolution and low temperature rise within the material during the curingstage significantly assists in preventing excessive thermal expansionand consequent cracking and disruption of material. This aspect isparticularly useful when the material is utilized in a manner wherelarge thicknesses of material pours are involved in the actual fieldapplications. The geopolymer cementitious compositions of the embodimentinvestigated in this Example are disclosed to be highly beneficial inthis particular aspect as they would lead to a lower thermal expansionand enhanced resistance to thermal cracking in actual fieldapplications.

Time of Setting

TABLE 39 shows the time of setting of geopolymer cementitiouscompositions of the embodiment investigated in Example 12.

TABLE 39 Setting Times of Example 12 Initial Setting Time (hr:min) FinalSetting Time (hr:min) Mix 1 00:40 1:10 Mix 2 00:30 1:12 Mix 3 00:36 1:05Mix 4 00:35 0:58

Increasing the amount of sodium citrate from about 2% to about 5% didnot modify the time of final setting of the investigated mixturecompositions to significant degree. The time of final setting for thefour geopolymer cementitious compositions of the embodiment investigatedin this Example ranged between about 60 minutes to about 110 minutes.

Compressive Strength

TABLE 40 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment comprising flyash, calcium sulfoaluminate cement, calcium sulfate dihydrate(fine-grained landplaster), and varying levels of alkali metal citrateinvestigated in Example 12.

TABLE 40 Compressive Strength of Example 12 - (psi) 4 hour 24 hour 7 day28 day Mix 1 2182 4038 4829 6799 Mix 2 2082 4216 5551 8008 Mix 3 23613954 4859 7460 Mix 4 2474 3790 5740 6920

The following important observations can be drawn from the study of thisembodiment:

The compressive strength of the geopolymer cementitious compositions ofthe embodiment investigated in this Example continued to increase withtime.

The early age (4-hour and 24-hour) compressive strengths of the variousgeopolymer cementitious compositions of this embodiment weresubstantially similar at the different amounts of sodium citrateinvestigated in this example.

The early age 4-hour material compressive strengths for the variousgeopolymer cementitious compositions of the embodiment investigated inthis example containing different amounts of sodium citrate were foundto be in excess of about 2000 psi.

The early age 24-hour material compressive strengths for the variousgeopolymer cementitious compositions of the embodiment investigated inthis example containing different amounts of sodium citrate were foundto be about 4000 psi.

The 28-day material compressive strengths for the various geopolymercementitious compositions of the embodiment investigated in this examplecontaining different amounts of sodium citrate were found to be inexcess of about 6000 psi.

Example 13

An objective of this investigation was to study the influence ofincorporation of anhydrous calcium sulfate (anhydrite) in the geopolymerbinder compositions of this embodiment.

TABLE 41 shows the raw material compositions of the geopolymercementitious mixtures in this example.

The amount of FASTROCK 500 calcium sulfoaluminate cement used in themixture compositions of this Example was equal to 80 wt % of the weightof fly ash. Anhydrite used in this investigation was procured from theUnited States Gypsum Company with the trade name USG SNOW WHITE brandfiller. Anhydrite was added at the following amount levels in themixture compositions investigated—0 wt %, 10 wt %, 20 wt % and 30 wt %of the weight of calcium sulfoaluminate cement. Anhydrite was added inlevels of 0, 8, 16 and 24 wt. %, based upon the weight of Class C flyash. Sodium citrate (an alkali metal citrate) added to the cementitiouscompositions of the invention acted as a chemical activator. The waterto cementitious materials ratio was kept constant at 0.30.

TABLE 41 Geopolymer cementitious compositions of Example 13 ComparativeRaw Material Mix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C 1666 1595 1530 1470(grams) Anhydrous Calcium 0 128 245 353 Sulfate (Anhydrite) (grams)Calcium Sulfoaluminate 1333 1277 1224.5 1176.5 Cement (grams) TotalCementitious 3000 3000 3000 3000 Materials (grams) Sand (grams) 31503150 3150 3150 Sodium Citrate 60 60 60 60 Dihydrate (grams)Superplasticizer 15 15 15 15 (grams) Water (grams) 900 900 900 900Water/Cementitious 0.30 0.30 0.30 0.30 Materials Ratio Sand/ 1.05 1.051.05 1.05 Cementitious Materials Ratio Superplasticizer/ 0.5% 0.5% 0.5%0.5% Cementitious Materials, wt % Sodium Citrate/ 2.0% 2.0% 2.0% 2.0%Cementitious Materials, wt % Calcium Sulfoaluminate 80% 80% 80% 80%cement/Fly ash, wt % Calcium Sulfate/ 0% 10% 20% 30% CalciumSulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 42 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of the embodiment comprisingfly ash, calcium sulfoaluminate cement, anhydrite, and alkali metalcitrate investigated in Example 13.

TABLE 42 Flow and Slump of Example 13 Flow Slump (inches) Mix 1 10 10.5Mix 2 10 11 Mix 3 10 10.25 Mix 4 10 10

All mixture compositions investigated had good self-leveling, flowbehavior and large patty diameter as observed in the slump test.

FIG. 13A shows photographs of slump patties for the mixes investigatedin Example 13. It can be observed that all four mixture compositionsinvestigated led to a good flow behavior. It can also be observed thatfor Mix #1 with no anhydrite, the slump patty developed significantcracking upon drying. However, for the geopolymer cementitiouscompositions of this embodiment containing anhydrite (Mixes 2, 3 and 4),the slump patties were in excellent condition and did not develop anycracking. Thus, it can be concluded addition of anhydrite to thegeopolymer cementitious compositions of this embodiment providedimensionally stable binders possessing superior resistance to crackingupon drying.

Shrinkage Behavior

FIG. 13B shows shrinkage behavior of geopolymer cementitiouscompositions of the embodiment investigated in Example 13.

The following important conclusions can be drawn from this investigationand FIG. 13B:

Incorporation of anhydrite had a significant impact on improving thecracking resistance and dimensional stability of the geopolymercementitious compositions of this embodiment comprising fly ash, calciumsulfoaluminate cement and alkali metal citrate. Contrary to theshrinkage bars of Comparative Example 4 (with no calcium sulfate) whichcracked even before de-molding, the shrinkage bars of Example 13comprising anhydrous calcium sulfate (anhydrite) were stable and did notresult in any cracks either prior to or after de-molding.

The geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, anhydrite, and alkali metalcitrate had a maximum shrinkage of about 0.05% to about 0.2% incomparison to a maximum shrinkage of about 0.75% for the comparativemixture composition containing fly ash and alkali metal citrate only(Example 1). Thus, it can be concluded addition of anhydrous calciumsulfate (anhydrite) to cementitious compositions comprising fly ash,calcium sulfoaluminate cement, and alkali metal citrate can help to verysignificantly reduce the material shrinkage.

The measured maximum shrinkage of the fly ash mixture compositioncontaining anhydrite at an amount of about 10 wt % of calciumsulfoaluminate cement was about 0.05%; in contrast, the total shrinkageof Mix 1 with fly ash and calcium sulfoaluminate cement but no anhydrouscalcium sulfate (anhydrite) was about 0.2%. This result demonstratesthat incorporation of anhydrous calcium sulfate (anhydrite) in thegeopolymer cementitious compositions of this embodiment contributes tosignificantly reducing the material shrinkage.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 13C shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of the embodiment investigated inExample 13. The cementitious compositions of this Example comprising flyash, calcium sulfoaluminate cement, anhydrite, and alkali metal citratedemonstrated only a moderate temperature rise behavior. A moderate heatevolution and low temperature rise within the material during the curingstage significantly contributes to preventing excessive thermalexpansion and consequent cracking and disruption of material. Thisaspect is particularly helpful when the material is utilized in a mannerwhere large thicknesses of material pours are involved in the actualfield applications. The geopolymer cementitious compositions of thisembodiment investigated in this Example are disclosed to be highlybeneficial in this particular aspect as they would lead to a lowerthermal expansion and enhanced resistance to thermal cracking in actualfield applications.

Time of Setting

TABLE 43 shows the time of setting of geopolymer cementitiouscompositions of the embodiment investigated in Example 1

TABLE 43 Setting Times of Example 13 Initial Setting Time (hr:min) FinalSetting Time (hr:min) Mix 1 00:28 00:43 Mix 2 00:21 00:41 Mix 3 00:2400:45 Mix 4 00:25 00:46

The final setting times of the geopolymer cementitious compositions ofthe embodiment of this Example comprising fly ash, calciumsulfoaluminate cement, anhydrite, and sodium citrate were over 40minutes compared to an extremely rapid final setting time of about 15minutes for the comparative mixture composition containing fly ash andsodium citrate only (Example 1). Thus, it can be concluded that additionof a mixture of calcium sulfoaluminate cement and anhydrite to a mixtureof fly ash and alkali metal citrate is helpful in extending the materialsetting and hardening behavior and making the material more userfriendly.

Compressive Strength

TABLE 44 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment comprising flyash, calcium sulfoaluminate cement, anhydrite, and alkali metal citrateinvestigated in Example 13.

TABLE 44 Compressive Strength of Example 13 - (psi) 4 hour 24 hour 7 day28 day Mix 1 214 562 1202 4414 Mix 2 1992 3484 4213 6945 Mix 3 3273 44776165 7560 Mix 4 2971 5018 6739 9020

The following observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofthe embodiment investigated in this Example continued to increase withtime.

Both the early age compressive strength and the ultimate compressivestrength of the mixture composition without anhydrite (Mix 1) were lowerin comparison to those for the cementitious compositions of thisembodiment comprising anhydrite (Mixes 2 through 4).

The early age (4-hour and 24-hour) compressive strength of thegeopolymer cementitious compositions of this embodiment increased withincrease in the amount of anhydrite in the material.

The 4-hour material compressive strengths were in excess of about 2000psi with the use of anhydrite in the geopolymer cementitiouscompositions of this embodiment. Moreover, the 4-hour compressivestrength of Mix 3 and Mix 4 containing anhydrite were around about 3000psi. In contrast, in absence of anhydrite in the mixture composition,the 4-hour compressive strength of the material was less than about 300psi for Mix 1.

The use of anhydrite provides a higher 4-hour compressive strength thanlandplaster in the geopolymer cementitious compositions of thisembodiment. This conclusion is substantiated by comparing thecompressive strength testing results for the Example 13 and Example 7.

The early age 24-hour material compressive strengths were in excess ofabout 3000 psi with the use of anhydrite in the geopolymer cementitiouscompositions of this embodiment. Moreover, the about 24-hour compressivestrength of Mix 3 and Mix 4 containing anhydrite were in excess of about4000 psi and about 5000 psi, respectively. On the other hand, in absenceof anhydrite in the mixture composition, the about 24-hour compressivestrength of the material was relatively low being less than about 600psi for Mix 1.

The 28-day compressive strengths of all geopolymer cementitiouscompositions of this embodiment comprising fly ash, calciumsulfoaluminate, anhydrite and sodium citrate were again very high and inexcess of about 6000 psi. At higher amounts of anhydrite in thecompositions (Mix 3 and Mix 4) of this embodiment, the 28-daycompressive strengths exceeded about 7000 psi. In comparison, the about28-day compressive strength of the material without anhydrite (Mix 1)was only about 4500 psi.

Thus it has been very surprisingly found that the use of insolubleanhydrous calcium sulfate (anhydrite or dead burnt anhydrite) provided afaster set, a superior rate of compressive strength development, and ahigher ultimate compressive strength than those obtained with the use ofa relatively higher soluble calcium sulfate dihydrate (see Example 7).

Another unexpected feature of embodiments of this invention is thedependence of setting behavior and compressive strength on the type ofcalcium sulfate used in the compositions of the invention, as shown inthis Example 13 through 18.

Example 14 Anhydrous Calcium Sulfate (Anhydrite)

An objective of this investigation was to study the influence ofincorporation of anhydrous calcium sulfate (anhydrite) in the geopolymerbinder compositions of this embodiment.

TABLE 45 shows the raw material compositions of the geopolymercementitious mixtures investigated in this Example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisExample was equal to 80 wt % of the weight of fly ash. Anhydrous calciumsulfate (anhydrite) was added at the following amount levels in themixture compositions investigated—40 wt %, 50 wt %, 60 wt % and 80 wt %of the weight of calcium sulfoaluminate cement. The anhydrite was usedat levels of 32, 40, 48 and 64 wt. % of the Class C fly ash. The waterto cementitious materials ratio utilized in this investigation was keptconstant at 0.3.

TABLE 45 Geopolymer cementitious compositions of Example 14 Raw MaterialMix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 1415 1364 1316 1229.5Anhydrous calcium sulfate 453 545.5 632 787 (Anhydrite) (grams) CalciumSulfoaluminate Cement 1133 1091 1053 984 (grams) Total CementitiousMaterials 3000 3000 3000 3000 (grams) Sand (grams) 3150 3150 3150 3150Sodium Citrate Dihydrate (grams) 60 60 60 60 Superplasticizer (grams) 1515 15 15 Water (grams) 900 900 900 900 Water/Cementitious Materials 0.300.30 0.30 0.30 Ratio Sand/Cementitious Materials 1.05 1.05 1.05 1.05Ratio Superplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5% Materials, wt %Sodium Citrate/Cementitious 2.0% 2.0% 2.0% 2.0% Materials, wt % CalciumSulfoaluminate  80%  80%  80%  80% Cement/Fly ash, wt % CalciumSulfate/Calcium  40%  50%  60%  80% Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 46 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of the embodiment comprisingfly ash, calcium sulfoaluminate cement, anhydrite, and alkali metalcitrate investigated in Example 14.

TABLE 46 Flow and Slump of Example 14, approx. amounts Flow Slump(inches) Mix 1 9 9.75 Mix 2 8 9.75 Mix 3 8 9.5 Mix 4 6 7.25

All mixture compositions investigated had good self-leveling, flowbehavior and large patty diameter as observed in the slump test.

All four mixture compositions investigated in Example 14 led to a goodflow behavior. For the mixes containing anhydrite the slump patties werein excellent condition and did not develop any cracking. Thus, additionof anhydrite to the geopolymer cementitious compositions of thisembodiment led to dimensionally stable compositions possessing superiorresistance to cracking upon drying.

Shrinkage Behavior

FIG. 14 shows shrinkage behavior of geopolymer cementitious compositionsof the embodiment investigated in Example 14.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 14:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate) which cracked even before de-molding, the shrinkage bars ofExample 14 comprising anhydrite were stable and did not result in anycracks either prior to or after de-molding.

The geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, anhydrite, and alkali metalcitrate had a maximum shrinkage less than about 0.17% in comparison to amaximum shrinkage of about 0.75% for the comparative mixture compositioncontaining fly ash and alkali metal citrate only (Example 1).

The measured maximum shrinkage of the fly ash mixture compositioncontaining anhydrite at an amount of about 40 wt % of calciumsulfoaluminate cement was about 0.2%. In contrast, the total shrinkageof comparative Mix 1 of Example 13 with fly ash and calciumsulfoaluminate cement but no anhydrite was about 0.2%. This showsincorporation of anhydrite in the geopolymer cementitious compositionsof this embodiment is instrumental in reducing the material shrinkagesignificantly.

Increase in anhydrite amount beyond a certain level had an effect ofincreasing the shrinkage of the material. For instance, at an anhydriteamount of about 10 wt % (Mix 2 of Example 13), the measured maximumshrinkage was about 0.05%, while at an anhydrite amount of about 80 wt %(Mix 4 of Example 14), the measured maximum shrinkage increased to avalue of about 0.17%.

Comparing the shrinkage testing results from Example 13 and Example 14,there is a preferred anhydrite amount range at which the materialshrinkage is minimal. This preferred range of anhydrite falls above 0but less than or equal to about 40 wt. % of the weight of calciumsulfoaluminate cement.

Time of Setting

TABLE 47 shows the time of setting of geopolymer cementitiouscompositions of the embodiment in Example 14.

TABLE 47 Setting Times of Example 14 Initial Setting Time (hr:min) FinalSetting Time (hr:min) Mix 1 00:24 00:46 Mix 2 00:24 00:46 Mix 3 00:2300:46 Mix 4 00:24 00:47

Advantageously the final setting times of the geopolymer cementitiouscompositions of the embodiment of this Example comprising fly ash,calcium sulfoaluminate cement, anhydrite, and sodium citrate were overabout 40 minutes compared to an extremely rapid final setting time ofabout 15 minutes for the comparative mixture composition containing flyash and sodium citrate only (Example 1).

Compressive Strength

Table 48 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment comprising flyash, calcium sulfoaluminate cement, anhydrite, and alkali metal citrateinvestigated in Example 14.

TABLE 48 Compressive Strength of Example 14 - (psi) 4 hour 24 hour 6 day28 day Mix 1 3205 4677 5853 8848 Mix 2 2489 5066 5637 8121 Mix 3 26034322 5520 7222 Mix 4 2317 4478 6267 8254

The following important observations can be drawn from this study: Thecompressive strength of the geopolymer cementitious compositions of theembodiment investigated in this Example continued to increase with time.

Both the early age compressive strength and the ultimate compressivestrength of the comparative mixture composition without anhydrite(Comparative Mix 1 of Example 13) were lower in comparison to those forthe mixes containing anhydrite (Mixes 1 through 4 of Example 14).

The 4-hour material compressive strengths were in excess of about 2000psi with the use of anhydrite in the geopolymer cementitiouscompositions of this embodiment. Moreover, the 4-hour compressivestrength of Mix 1 containing anhydrite at an amount of about 40% was inexcess of about 3000 psi. In contrast, in absence of anhydrite in thecomparative mixture composition, the 4-hour compressive strength of thematerial was relatively very low being less than about 300 psi, as seenfor the comparative Mix 1 of Example 13.

The use of anhydrite provides a higher 4-hour compressive strength thanlandplaster in the geopolymer cementitious compositions of thisembodiment. This conclusion is substantiated by a comparison of thecompressive strength testing results for the Example 14 and Example 8.

The early age 24-hour material compressive strength was in excess ofabout 4000 psi with the use of anhydrite in the geopolymer cementitiouscompositions of this embodiment. On the other hand, in absence ofanhydrite in the mixture composition, the 24-hour compressive strengthof the material was relatively very low being less than about 600 psi,as seen for the comparative Mix 1 of Example 13.

The 28-day compressive strength of all geopolymer cementitiouscompositions of this embodiment comprising fly ash, calciumsulfoaluminate cement, anhydrite and sodium citrate was again very highand in excess of about 7000 psi. In comparison, the 28-day compressivestrength of the material without anhydrite was only about 4500 psi forthe comparative Mix #1 of Example 13.

As discussed above in the description, testing of the compositions ofthis example demonstrates that anhydrite reacted with aluminosilicatemineral, calcium sulfoaluminate cement, and alkali metal activator givesa more rapid set, a faster rate of material compressive strengthdevelopment, and higher ultimate compressive strength in comparison tothose obtained with calcium sulfate dihydrate in other Examples.

Example 15 Calcium Sulfate Hemihydrate

An objective of this investigation was to study the influence ofincorporation of calcium sulfate hemihydrate at varying amounts in thegeopolymer binder compositions of this embodiment.

TABLE 49 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example.

The amount of calcium sulfoaluminate cement used in the mixturecompositions of this Example was equal to 80 wt % of the weight of flyash. Calcium sulfate hemihydrate used in this investigation was procuredfrom the United States Gypsum Company with trade name HYDROCAL C-Base.HYDROCAL C-Base is alpha morphological form of calcium sulfatehemihydrate. Calcium sulfate hemihydrate was added at the followingamount levels in the mixture compositions investigated—0 wt %, 10 wt %,20 wt % and 30 wt % of the weight of calcium sulfoaluminate cement. Thecalcium sulfate hemihydrate levels are 0, 8, 16 and 24 wt. % of the flyash. Sodium citrate (an alkali metal citrate) added to the cementitiouscompositions of the invention acted as a chemical activator, rheologymodifier, and set control agent. The water to cementitious materialsratio utilized in this investigation was kept constant at 0.30. The sandused is QUIKRETE Commercial Grade Fine Sand No. 1961 and theSuperplasticizer is BASF CASTAMENT FS20.

TABLE 49 Geopolymer cementitious compositions of Example 15 ComparativeMix 1 Mix 2 Mix 3 Mix 4 Weight Weight Weight Weight Raw Material (grams)(grams) (grams) (grams) Fly Ash Class C (grams) 1668 1596 1531 1471Calcium Sulfate 0 128 245 353 Hemihydrate (grams) Calcium Sulfoaluminate1333 1277 1224.5 1176.5 Cement (grams) Total Cementitious 3000 3000 30003000 Materials (grams) Sand (grams) 3150 3150 3150 3150 Sodium CitrateDihydrate 60 60 60 60 (grams) Superplasticizer (grams) 15 15 15 15 Water(grams) 900 900 900 900 Water/Cementitious 0.30 0.30 0.30 0.30 MaterialsRatio Sand/Cementitious 1.05 1.05 1.05 1.05 Materials RatioSuperplasticizer/ 0.50% 0.50% 0.50% 0.50% Cementitious Materials, wt %Sodium Citrate/   2%   2%   2%   2% Cementitious Materials, wt % CalciumSulfoaluminate  80%  80%  80%  80% Cement/Fly ash, wt % Calcium Sulfate 0%  10%  20%  30% Hemihydrate/Calcium Sulfoaluminate Cement. wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial.

TABLE 50 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of the embodiment comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate hemihydrate, andalkali metal citrate in Example 15.

TABLE 50 Flow and Slump of Example 15 Flow Slump (inches) Mix 1 11 10.5Mix 2 10 9 Mix 3 8 8 Mix 4 8 8

All mixture compositions investigated had good self-leveling, flowbehavior and large patty diameter as observed in the slump test.

All mixes had good flow characteristics and self-leveling behavior. Theslump patties of mixes containing calcium sulfate hemihydrate were inexcellent condition and did not develop any cracking. Thus, addition ofcalcium sulfate hemihydrate to the geopolymer cementitious compositionsof this embodiment comprising calcium sulfoaluminate cement, fly ash,and alkali metal citrate provides dimensionally stable compositionspossessing superior resistance to cracking upon drying.

Shrinkage Behavior

FIG. 15A shows shrinkage behavior of geopolymer cementitiouscompositions of the embodiment investigated in Example 15.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 15A:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate) which cracked even before de-molding, the shrinkage bars ofExample 15 comprising calcium sulfate hemihydrate were stable and didnot result in any cracks either prior to or after de-molding.

The geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate hemihydrate, andalkali metal citrate had a measured maximum shrinkage ranging of about0.08% to about 0.16% in comparison to a measured maximum shrinkage ofabout 0.75% for the comparative mixture composition containing fly ashand alkali metal citrate only (Example 1).

The measured maximum shrinkage of the fly ash mixture compositioncontaining calcium sulfate hemihydrate at an amount of about 10 wt % ofcalcium sulfoaluminate cement was about 0.08%. In contrast, the totalshrinkage of comparative Mix 1 with fly ash and calcium sulfoaluminatecement but no calcium sulfate hemihydrate was about 0.2%. This showsincorporation of calcium sulfate hemihydrate in the geopolymercementitious compositions of this embodiment reduces material shrinkagesignificantly.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 15B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of this embodiment in Example 15.The cementitious compositions of this Example comprising fly ash,calcium sulfoaluminate cement, calcium sulfate hemihydrate, and alkalimetal citrate demonstrated only a very moderate temperature risebehavior. A moderate heat evolution and low temperature rise within thematerial during the curing stage contribute to preventing excessivethermal expansion and consequent cracking and disruption of material.This aspect becomes even more helpful when the material is utilized in amanner where large thicknesses of material pours are involved in theactual field applications. The geopolymer cementitious compositions ofthis embodiment investigated in this Example are disclosed to be highlybeneficial in this particular aspect as they would lead to a lowerthermal expansion and enhanced resistance to thermal cracking in actualfield applications.

Time of Setting

TABLE 51 shows the time of setting of geopolymer cementitiouscompositions of the embodiment in Example 15.

TABLE 51 Setting Times of Example 15 Initial Setting Time Final SettingTime (hr:min) (hr:min) Comparative Mix 1 00:25 00:40 Mix 2 00:39  1:29Mix 3  1:01  1:38 Mix 4  1:12  1:46

The final setting times of the geopolymer cementitious compositions ofthe embodiment of this Example comprising fly ash, calciumsulfoaluminate cement, calcium sulfate hemihydrate, and sodium citratewere over about 90 minutes compared to an extremely rapid final settingtime of about 15 minutes for the comparative mixture compositioncontaining fly ash and sodium citrate only (Example 1).

As discussed above in the description, a comparison of the test resultsof this Example with the setting times in Example 13 and Example 7,shows that calcium sulfate hemihydrate is unexpectedly more potent thanboth anhydrite and landplaster in extending the setting times of thecompositions containing fly ash, calcium sulfoaluminate cement andalkali metal citrate.

Compressive Strength

TABLE 52 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment in Example 15.

TABLE 52 Approx. Compressive Strength of Example 15 - (psi) 4 hour 24hour 7 day 28 day Comparative Mix 1 238 532 1708 3879 Mix 2 1396 34824416 5571 Mix 3 3096 4517 6570 7181 Mix 4 3418 4931 6913 7267

The following observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofthis embodiment continued to increase as a function of time.

Both the early age compressive strength and the ultimate compressivestrength of the mixture composition without calcium sulfate hemihydrate(Mix 1) were lower in comparison to those for the cementitiouscompositions of this embodiment comprising calcium sulfate hemihydrate(Mixes 2 through 4).

The early age (about 4-hour and about 24-hour) compressive strength ofthe geopolymer cementitious compositions of this embodiment increasedwith increase in the quantity of calcium sulfate hemihydrate in thematerial.

The 4-hour material compressive strength was in excess of about 1000 psiwith the use of calcium sulfate hemihydrate in the geopolymercementitious compositions of this embodiment. Moreover, the 4-hourcompressive strengths of Mix 3 and Mix 4 containing calcium sulfatehemihydrate were in excess of about 3000 psi. On the other hand, themixture composition containing no calcium sulfate hemihydrate, the4-hour compressive strength of the material was very low being i.e. lessthan about 300 psi for Mix 1.

The use of calcium sulfate hemihydrate provides a higher 4-hourcompressive strength than landplaster in the geopolymer cementitiouscompositions of this embodiment. This conclusion is substantiated bymaking a comparison of the compressive strength testing results for theExample 15 with those of the Example 7.

The about 24-hour material compressive strength was in excess of about3000 psi with the use of calcium sulfate hemihydrate in the geopolymercementitious compositions of this embodiment. Moreover, the about24-hour compressive strength of Mix 3 and Mix #4 geopolymer cementitiouscompositions of this embodiment comprising fly ash, calciumsulfoaluminate, anhydrite and sodium citrate containing calcium sulfatehemihydrate was in excess of about 4000 psi. In contrast, for thecomparative mixture composition containing no calcium sulfatehemihydrate, the about 24-hour compressive strength of the material wasrelatively very low being less than about 600 psi for Mix 1.

The about 28-day compressive strength of all geopolymer cementitiouscompositions of this embodiment comprising fly ash, calciumsulfoaluminate, anhydrite and sodium citrate was again very high and inexcess of about 5000 psi. At higher amounts of calcium sulfatehemihydrate in the compositions (Mix 3 and Mix 4) of this embodiment,the 28-day compressive strength exceeded about 7000 psi. In comparison,the 28-day compressive strength of the comparative material withoutcalcium sulfate hemihydrate (Mix 1) was found to be less than about 4000psi.

Example 16

An objective of this investigation was to study the influence ofincorporation of calcium sulfate hemihydrate at varying amounts in thegeopolymer binder compositions of this embodiment.

TABLE 53 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example. FASTROCK 500 brandcalcium sulfoaluminate cement, available from CTS Cement Company wasagain utilized as a component of cementitious reactive powder. Theamount of calcium sulfoaluminate cement used in the mixture compositionsof this Example was 80 wt % of the weight of Class C fly ash. Calciumsulfate hemihydrate, USG HYDROCAL C-Base, was added at the followingamount levels in the mixture compositions investigated—40 wt %, 50 wt %,60 wt % and 80 wt % of the weight of calcium sulfoaluminate cement. Thecalcium sulfate hemihydrate was used in levels of 32, 40 48 and 64 wt. %of the fly ash. The water to cementitious materials ratio utilized inthis investigation was kept constant at 0.30. The sand is QUIKRETECommercial Grade Fine Sand No. 1961 and the superplasticizer is BASFCASTAMENT FS20.

TABLE 53 Geopolymer cementitious compositions of Example 16 Raw MaterialMix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 1415 1364 1316 1230Calcium Sulfate Hemihydrate 453 546 633 787 (grams) CalciumSulfoaluminate 1132 1091 1053 984 Cement (grams) Total CementitiousMaterials 3000 3000 3000 3000 (grams) Sand (grams) 3150 3150 3150 3150Sodium Citrate Dihydrate 60 60 60 60 (grams) Superplasticizer (grams) 1515 15 15 Water (grams) 900 900 900 900 Water/Cementitious Materials 0.300.30 0.30 0.30 Ratio Sand/Cementitious Materials 1.05 1.05 1.05 1.05Ratio Superplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5% Materials, wt %Sodium Citrate/Cementitious   2%   2%   2%   2% Materials, wt % CalciumSulfoaluminate  32%  80%  80%  80% cement/Fly ash, wt % CalciumSulfate/Calcium  40%  50%  60%  80% Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 54 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate hemihydrate, andalkali metal citrate investigated in Example 16.

TABLE 54 Flow and Slump of Example 16, in approx. amounts Flow Slump(inches) Mix 1 9 8.25 Mix 2 9 8.25 Mix 3 9 8 Mix 4 8 7.75

All mixture compositions investigated had good self-leveling, flowbehavior and large patty diameter as observed in the slump test.

FIG. 16A shows photographs of slump patties for the mixes investigatedin Example 16. All mixes had good flow characteristics and self-levelingbehavior. It can also be observed that for the Mixes 2, 3 and 4containing calcium sulfate hemihydrate, the slump patties developed somemicrocracking. Thus, it can be concluded that addition of calciumsulfate hemihydrate at high amount levels to mixtures containing calciumsulfoaluminate cement, fly ash and alkali metal citrate providescementitious compositions possessing relatively inferior resistance tomicrocracking upon drying.

Shrinkage Behavior.

FIG. 16B shows shrinkage behavior of geopolymer cementitiouscompositions of this embodiment investigated in Example 16 incorporatingcalcium sulfoaluminate cement in combination with calcium sulfatehemihydrate and an alkali metal citrate.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following conclusions can be drawn from this investigation and FIG.16 c:

The geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate hemihydrate, andalkali metal citrate had a measured maximum shrinkage of less than about0.44% in comparison to a measured maximum shrinkage of about 0.75% forthe comparative mixture composition containing fly ash and alkali metalcitrate only (Example 1).

Increase in calcium sulfate hemihydrate amounts increased the shrinkageof the material. For instance, at a calcium sulfate hemihydrate amountof about 10 wt % (Mix 1 of Example 15), the total shrinkage was about0.08%. At a calcium sulfate hemihydrate amount of about 80 wt % (Mix 4of Example 16), the total shrinkage of the material increased verysignificantly to a value of about 0.44%.

Comparing the shrinkage testing results from Example 15 and Example 16,it can be concluded there exists a preferred calcium sulfate hemihydrateamount range at which the material shrinkage is minimal. This preferredrange of calcium sulfate hemihydrate falls in a range from above about0% to less than or equal to about 40 wt % of the weight of calciumsulfoaluminate cement.

Time of Setting

TABLE 55 shows the time of setting of geopolymer cementitiouscompositions of this embodiment in Example 16.

TABLE 55 Approx. Setting Times of Example 16 Initial Setting Time(hr:min) Final Setting Time (hr:min) Mix 1 1:12 2:11 Mix 2 1:14 2:13 Mix3 1:20 2:12 Mix 4 1:18 2:13

All cementitious compositions investigated in this Example demonstratedrapid setting behavior. The final setting times of the geopolymercementitious compositions of the embodiment of this Example comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate hemihydrate, andsodium citrate were around 120 minutes compared to an extremely rapidfinal setting time of about 15 minutes for the comparative mixturecomposition containing fly ash and sodium citrate only (Example 1).

Comparing the testing results of this Example with those of Example 15and Example 8, indicates calcium sulfate hemihydrate is more potent thanboth anhydrite and landplaster in extending the setting times of themixture compositions containing fly ash, calcium sulfoaluminate cementand alkali metal citrate.

The use of calcium sulfate hemihydrate as the form of calcium sulfateprovided a much longer set time in comparison to the set time obtainedwith the use of calcium sulfate dihydrate (see Example 7). As discussedabove in the description, this result was unexpected because it is wellknown in the art that calcium sulfate hemihydrate is an extremely rapidsetting material. Addition of calcium sulfate hemihydrate in someembodiments of the compositions of invention provided extended settingtimes in comparison to embodiments with calcium sulfate dihydrate andanhydrous calcium sulfate

Compressive Strength

TABLE 56 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of this embodiment comprising flyash, calcium sulfoaluminate cement, calcium sulfate hemihydrate, andalkali metal citrate in Example 16.

TABLE 56 Compressive Strength of Example 16 - (psi) 4 hour 24 hour 7 day28 day Mix 1 2714 5374 6971 8142 Mix 2 2299 5385 6722 8061 Mix 3 19404921 6820 7684 Mix 4 1536 4420 6721 8911

The following important observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofthe embodiment investigated in this Example continued to increase withtime.

Both the early age compressive strength and the ultimate compressivestrength of the mixture composition without calcium sulfate hemihydrate(Mix 1 of Example 15) were lower in comparison to those for thecementitious compositions of this embodiment comprising calcium sulfatehemihydrate (Mixes 1 through 4 of Example 16).

The 4-hour material compressive strength was in excess of about 1500 psiwith the use of calcium sulfate hemihydrate in the geopolymercementitious compositions of this embodiment. Moreover, the 4-hourcompressive strength of Mix 1 containing calcium sulfate hemihydrate atan amount of about 40% was in excess of about 2500 psi. In contrast, forthe comparative mixture composition containing no calcium sulfatehemihydrate (Mix 1 of Example 15), the 4-hour compressive strength ofthe material was relatively very low being less than about 300 psi.

The use of calcium sulfate hemihydrate provides a higher 4-hourcompressive strength than landplaster in the geopolymer cementitiouscompositions of this embodiment. This is shown by a comparison of thecompressive strength testing results for Example 16 with those ofExample 8.

The about 24-hour material compressive strength was in excess of about4000 psi with the use of calcium sulfate hemihydrate in the geopolymercementitious compositions of this embodiment. On the other hand, for thecomparative mixture composition comprising no calcium sulfatehemihydrate (Mix 1 of Example 15), the about 24-hour compressivestrength of the material was relatively low at less than about 600 psi.

The 28-day compressive strength of all geopolymer cementitiouscompositions of this embodiment comprising fly ash, calciumsulfoaluminate cement, calcium sulfate hemihydrate and sodium citratewas very high i.e. in excess of about 7000 psi. In comparison, the28-day compressive strength of the comparative material without calciumsulfate hemihydrate (Mix 1 of Example 15) was less than about 4000 psi.

Example 17 Coarse-Grained Calcium Sulfate Dihydrate

An objective of this investigation was to study the influence ofincorporation of coarse-grained calcium sulfate dihydrate in thegeopolymer binder compositions of this embodiment.

TABLE 57 shows the raw material compositions of the geopolymercementitious mixtures investigated_in this example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisexample was 80 wt % of the weight of Class C fly ash. Coarse-grainedcalcium sulfate dihydrate, otherwise identified here as coarselandplaster, was procured from the United States Gypsum Company and isavailable with the trade name USG Ben Franklin AG Coarse Gypsum. Coarselandplaster was added at different amount levels 0 wt %, 10 wt %, 20 wt%, and 30 wt % of the weight of FASTROCK 500 calcium sulfoaluminatecement in the various mixture compositions investigated. The landplasterwas added at levels of 0, 8, 16 and 24 wt. % based upon the weight offly ash. The sand used is QUIKRETE Commercial Grade Fine Sand No. 1961and the Superplasticizer is BASF CASTAMENT.

TABLE 57 Geopolymer cementitious compositions of Example 17 ComparativeRaw Material Mix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 1668 15961531 1471 Calcium Sulfate Dihydrate 0 128 245 353 (grams) CalciumSulfoaluminate 1333 1277 1225 1177 Cement (grams) Total Cementitious3000 3000 3000 3000 Materials (grams) Sand (grams) 3150 3150 3150 3150Sodium Citrate Dihydrate 60 60 60 60 (grams) Superplasticizer (grams) 1515 15 15 Water (grams) 900 900 900 900 Water/Cementitious 0.30 0.30 0.300.30 Materials Ratio Sand/Cementitious 1.05 1.05 1.05 1.05 MaterialsRatio Superplasticizer/ 0.5% 0.5% 0.5% 0.5% Cementitious Materials, wt %Sodium Citrate/   2%   2%   2%   2% Cementitious Materials, wt % CalciumSulfoaluminate  80%  80%  80%  80% cement/Fly ash, wt % CalciumSulfate/Calcium   0%  10%  20%  30% Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

Table 58 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, coarse-grained landplaster, andalkali metal citrate in Example 17.

TABLE 58 Flow and Slump of Example 17 Flow Slump (inches) Mix 1 10 11Mix 2 10 9.75 Mix 3 10 10.25 Mix 4 10 10.5

All mixture compositions investigated had good flow behavior and largepatty diameter as observed in the slump test.

FIG. 17A shows photographs of slump patties for the geopolymercementitious compositions of the embodiment investigated in Example 17.Comparative Mix 1 that did not contain any calcium sulfate(coarse-grained landplaster) and its slump patty developed significantcracking upon drying. However, for mixes containing coarse-grainedlandplaster, the slump patties were in excellent condition and did notdevelop any cracking. Thus, it can seen addition of coarse-grainedlandplaster to the cementitious mixtures comprising calciumsulfoaluminate cement, fly ash, and alkali metal citrate providesdimensionally stable geopolymer cementitious compositions with moderateheat evolution and low temperature rise within the material during thecuring stage to prevent excessive thermal expansion and consequentcracking and disruption of material upon drying.

Shrinkage Behavior

FIG. 17B shows shrinkage behavior of geopolymer cementitiouscompositions of the embodiment investigated in Example 17.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from the results ofthis investigation and FIG. 17B:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate) which cracked even before de-molding, the shrinkage bars ofExample 17 comprising coarse-grained landplaster (Mix 2, 3 and 4) werestable and did not result in any cracks prior to or after de-molding.

The geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, coarse-grained landplaster, andalkali metal citrate had a maximum shrinkage ranging of about 0.11% toabout 0.16% in comparison to a maximum shrinkage of about 0.75% for thecomparative mixture composition containing fly ash and alkali metalcitrate only (Example 1).

The mixture compositions Mixes 2, 3 and 4 comprising fly ash, calciumsulfoaluminate cement, calcium sulfate (coarse-grained landplaster), andalkali metal citrate had a maximum shrinkage ranging of about 0.11% toabout 0.16%, while the maximum shrinkage of the comparative Mix 1comprising fly ash, calcium sulfoaluminate cement, and alkali metalcitrate but no calcium sulfate (landplaster) was about 0.24%.

Increase in the coarse-grained landplaster amount in the rangeinvestigated in this Example resulted in an overall decrease in thematerial shrinkage. For example, at a coarse-grained landplaster amountof about 10 wt %, the measured maximum shrinkage was about 0.16%, whileat a coarse-grained landplaster amount of about 30 wt % the measuredmaximum shrinkage reduced to about 0.11%.

Comparing the shrinkage testing results from Example 7 and Example 17,indicates the use of a landplaster with finer particle size provides alower shrinkage. For example, with the use of coarse-grained landplasterof Example 17 at an amount of about 30 wt %, the maximum shrinkage wasabout 0.11%; on the other hand, with the use of fine-grained landplasterof Example 7, the maximum shrinkage was only about 0.06% at the samelandplaster amount of about 30 wt %.

Heat Development and Slurry Temperature Rise Behavior

FIG. 17C shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of the embodiment investigated inExample 17. The cementitious compositions of Example 17 comprising flyash, calcium sulfoaluminate cement, coarse-grained landplaster, andalkali metal citrate demonstrated only a very moderate temperature risebehavior. Furthermore, comparing the temperature rise testing resultsfor Example 17 and Example 7, indicates the use of coarse landplasterprovides a relatively lower temperature rise than that obtained with theuse of fine-grained landplaster. A moderate heat evolution and lowtemperature rise within the material during the curing stagesignificantly contributes to preventing excessive thermal expansion andconsequent cracking and disruption of material. This aspect becomes evenmore helpful when the material is utilized in a manner where largethicknesses of material pours are involved in the actual fieldapplications. The geopolymer cementitious compositions of the embodimentinvestigated in this Example are disclosed to be highly beneficial inthis particular aspect as they would lead to a lower thermal expansionand enhanced resistance to thermal cracking in actual fieldapplications.

Time of Setting

TABLE 59 shows the time of setting of geopolymer cementitiouscompositions of the embodiment in Example 17.

TABLE 59 Setting Times of Example 17 Initial Setting Time Final SettingTime (hr:min) (hr:min) Comparative Mix 1 00:23  00:45: Mix 2 00:27 00:57Mix 3 00:32 00:59 Mix 4 00:30 00:59

All cementitious compositions investigated in this Example demonstratedrapid setting behavior. The final setting times of the geopolymercementitious compositions of the embodiment of this Example comprisingfly ash, calcium sulfoaluminate cement, coarse-grained landplaster, andsodium citrate were about 60 minutes compared to an extremely rapidfinal setting time of about 15 minutes for the comparative mixturecomposition containing fly ash and sodium citrate only (Example 1).

Compressive Strength

TABLE 60 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of this embodiment comprising flyash, calcium sulfoaluminate cement, coarse-grained landplaster, andalkali metal citrate investigated in Example 17.

TABLE 60 Approx. Compressive Strength of Example 17 - (psi) 4 hour 24hour 7 day 28 day Comparative 206 568 1445 3965 Mix 1 Mix 2 266 10372489 4321 Mix 3 346 1683 3242 5708 Mix 4 400 1833 3727 5523

The following observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofthe embodiment investigated in this Example continued to increase withtime.

Both the early age compressive strength and the ultimate compressivestrength of the mixture composition without landplaster (Mix 1) werelower compared to those for the cementitious compositions of thisembodiment comprising coarse-grained landplaster (Mixes 2 through 4).

The early age (about 4-hour and about 24-hour) compressive strength ofthe geopolymer cementitious compositions of this embodiment increasedwith increase in the amount of coarse-grained landplaster in thematerial. However, the increase in 4-hour compressive strength obtainedwith an increase in coarse-grained landplaster content was only nominaland not very significant.

The early age 24-hour compressive strength of the material was in excessof about 1000 psi with the use of coarse-grained landplaster in thegeopolymer cementitious compositions of this embodiment.

The 28-day compressive strength of all geopolymer cementitiouscompositions of this embodiment comprising fly ash, calciumsulfoaluminate, coarse-grained landplaster and sodium citrate wasrelatively high, i.e., in excess of about 4000 psi. Moreover, the 28-daycompressive strength of the mixture compositions containing coarselandplaster at an amount of about 20 wt % and about 30 wt % (Mixes #3and #4) were particularly very high, in excess of about 5000 psi.

Comparing the testing results for Example 17 and Example 7, it can beseen that the use of finer landplaster provides a more rapid increase inthe 4-hour and 24-hour material compressive strengths, and a relativelyhigher 28-day material compressive strength.

Example 18

An objective of this investigation was to study the influence ofincorporation of coarse-grained calcium sulfate dihydrate in thegeopolymer binder compositions of the invention.

TABLE 61 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisExample was equal to 80 wt % of the weight of fly ash. Coarselandplaster was added at different amount levels (40 wt %, 50 wt %, 60wt %, and 80 wt % of the weight of calcium sulfoaluminate cement) in thevarious mixture compositions investigated. The landplaster was added atlevels of 32, 40, 48 and 64 wt. % of the Class C fly ash. The sand usedis QUIKRETE Commercial Grade Fine Sand No. 1961 and the Superplasticizeris BASF CASTAMENT.

TABLE 61 Geopolymer cementitious mixture compositions of Example 18 RawMaterial Mix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 1415 1364 13161230 Calcium Sulfate Dihydrate 453 546 632 787 (grams) CalciumSulfoaluminate 1133 1091 1053 984 Cement (grams) Total CementitiousMaterials 3000 3000 3000 3000 (grams) Sand (grams) 3150 3150 3150 3150Sodium Citrate Dihydrate 60 60 60 60 (grams) Superplasticizer (grams) 1515 15 15 Water (grams) 900 900 900 900 Water/Cementitious Materials 0.300.30 0.30 0.30 Ratio Sand/Cementitious Materials 1.05 1.05 1.05 1.05Ratio Superplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5% Materials, wt %Sodium Citrate/Cementitious   2%   2%   2%   2% Materials, wt % CalciumSulfoaluminate  80%  80%  80%  80% cement/Fly ash, wt % CalciumSulfate/Calcium  40%  50%  60%  80% Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 62 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of the embodiment comprisingfly ash, calcium sulfoaluminate cement, coarse-grained landplaster, andalkali metal citrate in Example 18.

TABLE 62 Flow and Slump of Example 18 Flow Slump (inches) Mix 1 10 10Mix 2 10 10 Mix 3 10 10 Mix 4 10 9.75

All mixture compositions investigated had good flow behavior and largepatty diameter as observed in the slump test.

The slump patties of all four mixture compositions of this Examplecomprising coarse-grained landplaster were in excellent condition anddid not develop any cracking. In contrast, the mixture compositioncontaining no calcium sulfate (landplaster) (Comparative Mix 1 ofExample 17) developed very significant cracking upon drying. Thus,incorporation of coarse-grained landplaster to the cementitious mixturescomprising calcium sulfoaluminate cement, fly ash, and alkali metalcitrate provides dimensionally stable geopolymer cementitiouscompositions possessing superior resistance to cracking upon drying.

Shrinkage Behavior

FIG. 18A shows shrinkage behavior of geopolymer cementitiouscompositions of the embodiment investigated in Example 18.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 18A:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate) which cracked even before de-molding, the shrinkage bars ofExample 18 comprising calcium sulfate (fine-grained landplaster) werestable and did not result in cracks that indicated unacceptabledimensional stability or undesired shrinkage either prior to or afterde-molding.

The geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, coarse-grained landplaster, andalkali metal citrate had a maximum shrinkage of about 0.09% incomparison to a maximum shrinkage of about 0.75% for the comparativemixture composition containing fly ash and alkali metal citrate only(Example 1). Thus, it can be concluded that addition of coarse-grainedlandplaster to cementitious compositions comprising fly ash, calciumsulfoaluminate cement, and alkali metal citrate helps to verysignificantly reduce the material shrinkage.

It can be observed that the geopolymer cementitious compositions of thisembodiment comprising fly ash, calcium sulfoaluminate cement,coarse-grained landplaster, and alkali metal citrate investigated inthis Example had a maximum shrinkage of about 0.09%. In contrast, themaximum shrinkage of comparative Mix 1 of Example 17 with fly ash andcalcium sulfoaluminate cement but no coarse landplaster was about 0.24%.

Increase in the coarse landplaster amount in the range investigated inthis Example did not result in any major change in the materialshrinkage behavior. For instance, at a coarse-grained landplaster amountrange of about 40 wt % to about 80 wt %, the measured maximum shrinkagefor different mixture compositions remained constant at about 0.09%.

Comparing the shrinkage testing results from Example 8 and Example 18,indicates when higher amount levels of calcium sulfate (>50 wt. %) areused in the mixture compositions, coarse-grained landplaster is moreeffective in reducing the overall material shrinkage.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 18B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of the embodiment investigated inExample 18. Comparing the temperature rise testing results for Example18 and Example 8, indicates the use of coarse-grained landplasterprovides a lower temperature rise than that obtained with the use offine-grained landplaster. A moderate heat evolution and low temperaturerise within the material during the curing stage significantlycontributes to preventing excessive thermal expansion and consequentcracking and disruption of material. This aspect also is helpful whenthe material is utilized in a manner where large thicknesses of materialpours are involved in the actual field applications. The geopolymercementitious compositions of the embodiments investigated in thisExample are disclosed to be highly beneficial in this particular aspectas they would lead to a lower thermal expansion and enhanced resistanceto thermal cracking in actual field applications.

Time of Setting

TABLE 63 shows the time of setting of geopolymer cementitiouscompositions of the embodiment in Example 18.

TABLE 63 Setting Times of Example 18 Initial Setting Time Final SettingTime (hr:min) (hr:min) Mix 1 00:40 1:20 Mix 2 00:36 1:15 Mix 3 00:401:10 Mix 4 00:46 1:15

The final setting times of the geopolymer cementitious compositions ofthe embodiment of this Example comprising fly ash, calciumsulfoaluminate cement, coarse-grained landplaster, and sodium citratewere about 70 minutes compared to an extremely rapid final setting timeof about 15 minutes for the comparative mixture composition containingfly ash and sodium citrate only (Example 1).

Compressive Strength

TABLE 64 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment comprising flyash, calcium sulfoaluminate cement, coarse-grained landplaster, andalkali metal citrate in Example 18.

TABLE 64 Compressive Strength of Example 18 - (psi) 4 hour 24 hour 7 day28 day Mix 1 498 2090 4128 4172 Mix 2 539 2094 3602 4387 Mix 3 561 24083456 4622 Mix 4 542 2285 3270 4143

The following important observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofthe embodiment investigated in this Example continued to increase withtime.

Both the early age and the ultimate compressive strength of thecomparative mixture composition without landplaster (Mix 1) were lowerin comparison to those for the cementitious compositions of thisembodiment comprising coarse-grained landplaster (Mixes 2 through 4).

Comparing the testing results for Example 18 and Example 8, indicatesuse of finer landplaster provides a more rapid increase in 4-hourmaterial compressive strength. For instance, it can be observed thatwith the use of fine-grained landplaster in the mixture compositions ofExample 8, the 4-hour material compressive strength achieved were inexcess of about 1500 psi (Mixes #1 through #4 of Example 8).

The early age 24-hour compressive strength of the material was in excessof about 2000 psi with the use of coarse-grained landplaster as acomponent of the geopolymer cementitious compositions of thisembodiment. Comparing the testing results for Example 18 and Example 8,it can be concluded that use of finer landplaster provides a more rapidincrease in the 24-hour material compressive strength. For instance, itcan be observed that with the use of fine-grained landplaster in themixture compositions of Example 8, the 24-hour material compressivestrength achieved was in excess of about 4000 psi (Mixes 1, 2, and 3 ofExample 8).

The 28-day compressive strength of all geopolymer cementitiouscompositions of the embodiment comprising fly ash, calciumsulfoaluminate, coarse-grained landplaster and sodium citrate in thisExample was less than about 5000 psi. Comparing the testing results forExample 18 and Example 8, it can be seen that use of calcium sulfate(fine-grained landplaster) provides a relatively higher 28-day materialcompressive strength. For instance, the use of calcium sulfate(fine-grained landplaster) in the mixture compositions of Example 8, the28-day material compressive strengths achieved were in excess of about6000 psi (Mixes 1 through 3 of Example 8).

Example 19

An objective of this investigation was to study the influence ofincorporation of high purity, fine-grained calcium sulfate dihydrate atvarying amounts, in the geopolymer compositions of embodiments of theinvention.

TABLE 65 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example.

The amount of calcium sulfoaluminate cement used in the mixturecompositions of this Example was equal to 80 wt % of the weight of flyash. The fine-grained calcium sulfate dihydrate used in thisinvestigation was from USG Company with the trade name USG TERRA ALBAF&P. Calcium sulfate dihydrate was added at the following amount levelsin the mixture compositions investigated—0 wt %, 10 wt %, 20 wt % and 30wt % of the weight of calcium sulfoaluminate cement. The calcium sulfatedihydrate was added at levels of 0, 8, 16 and 24 wt. % of the Class Cfly ash. The water to cementitious materials ratio utilized in thisinvestigation was kept constant at 0.30. The sand used is QUIKRETECommercial Grade Fine Sand No. 1961 and the Superplasticizer is BASFCASTAMENT.

TABLE 65 Geopolymer cementitious mixture compositions of Example 19Comparative Raw Material Mix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams)16677 1596 1531 1471 Calcium Sulfate 0 128 245 353 Dihydrate(grams)Calcium Sulfoaluminate 1333 1277 1224.5 1176 Cement (grams) TotalCementitious Materials (grams) 3000 3000 3000 3000 Sand (grams) 31503150 3150 3150 Sodium Citrate Dihydrate (grams) 60 60 60 60Superplasticizer (grams) 15 15 15 15 Water (grams) 900 900 900 900Water/Cementitious Materials Ratio 0.30 0.30 0.30 0.30 Sand/CementitiousMaterials Ratio 1.05 1.05 1.05 1.05 Superplasticizer/Cementitious 0.5%0.5% 0.5% 0.5% Materials, wt % Sodium Citrate/Cementitious   2%   2%  2%   2% Materials, wt % Calcium Sulfoaluminate  80%  80%  80%  80%cement/Fly ash, wt % Calcium Sulfate/Calcium   0%  10%  20%  30%Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 66 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, fine-grained calcium sulfatedihydrate, and alkali metal citrate in Example 19.

TABLE 66 Flow and Slump of Example 19 Flow Slump (inches) Mix 1 10 11.25Mix 2 10 10.25 Mix 3 10 10.5 Mix 4 10 10.5

All mixture compositions investigated had good flow behavior and largepatty diameter as observed in the slump test.

The slump patty of comparative Mix #1 with no calcium sulfate developedsignificant cracking upon drying. However, for the mixes comprisingfine-grained calcium sulfate dihydrate, the slump patties were inexcellent condition and did not develop any cracking. Thus, addition offine-grained calcium sulfate dihydrate to the cementitious mixturescomprising calcium sulfoaluminate cement, fly ash, and alkali metalcitrate provides dimensionally stable compositions possessing superiorresistance to cracking upon drying.

Shrinkage Behavior.

FIG. 19A shows shrinkage behavior of geopolymer cementitiouscompositions of the embodiment investigated in Example 19.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 19 c:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate dihydrate) which cracked even before de-molding, the shrinkagebars of Example 19 comprising fine-grained calcium sulfate dihydratewere completely stable and did not result in any cracks either prior toor after de-molding.

The geopolymer cementitious compositions of the embodiment comprisingcalcium sulfoaluminate cement and fine-grained calcium sulfate dihydrateinvestigated in this Example had a maximum shrinkage ranging of about0.06% to about 0.08% in comparison to a maximum shrinkage of about 0.75%for the comparative mixture containing fly ash and alkali metal citrateonly (Example 1).

The geopolymer cementitious compositions (Mixes 2, 3 and 4) of thisembodiment comprising calcium sulfoaluminate cement and fine-grainedcalcium sulfate dihydrate had a maximum shrinkage of about 0.06% toabout 0.08%; on the other hand, the maximum shrinkage for thecomparative Mix 1 with fly ash and calcium sulfoaluminate cement but nofine-grained calcium sulfate was relatively very high at about 0.24%.

Increase in the fine-grained calcium sulfate dihydrate amount in therange investigated in this Example resulted in decrease in the overallmaterial shrinkage. For example, a fine-grained calcium sulfatedihydrate amount of about 10 wt % the measured maximum shrinkage wasabout 0.08%, while at a fine-grained calcium sulfate dihydrate amount ofabout 30 wt %, the measured maximum shrinkage reduced to about 0.06%.

Comparison of the shrinkage testing results from Example 7, Example 17and Example 19, indicates the use of fine-grained calcium sulfatedihydrate (fine-grained calcium sulfate dihydrate) provides loweroverall shrinkage. For example, with the use of coarse-grained calciumsulfate dihydrate of Example 17, the maximum shrinkage was equal toabout 0.11% at a calcium sulfate dihydrate amount of about 30 wt %, onthe other hand, with the use of fine-grained calcium sulfate dihydrateof Example 19, the maximum shrinkage was only about 0.06% at a calciumsulfate dihydrate amount of about 30 wt %.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 19B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of the embodiment investigated inExample 19. The cementitious compositions of Example 19 comprising flyash, calcium sulfoaluminate cement, fine-grained calcium sulfatedihydrate, and alkali metal citrate demonstrated only a very moderatetemperature rise behavior. A moderate heat evolution and low temperaturerise within the material during the curing stage significantlycontributes to preventing excessive thermal expansion and consequentcracking and disruption of material. This aspect is of particularassistance when the material is utilized in a manner where largethicknesses of material pours are involved in the actual fieldapplications. The geopolymer cementitious compositions of thisembodiment investigated in this Example are disclosed to be highlybeneficial in this particular aspect as they would lead to a lowerthermal expansion and enhanced resistance to thermal cracking in actualfield applications.

Time of Setting

TABLE 67 shows the time of setting of geopolymer cementitiouscompositions of the embodiment in Example 19.

TABLE 67 Setting Times of Example 19 Initial Setting Time (hr:min) FinalSetting Time (hr:min) Mix 1 00:35 1:24 Mix 2 00:49 1:12 Mix 3 00:41 1:21Mix 4 00:29 1:00

All cementitious compositions investigated in this Example demonstratedrapid setting behavior. The final setting times of the geopolymercementitious compositions of this embodiment were about 60 to about 90minutes compared to an extremely rapid final setting time of about 15minutes for the comparative mixture composition containing fly ash andsodium citrate only (Example 1).

Compressive Strength

TABLE 68 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment comprising flyash, calcium sulfoaluminate cement, fine-grained calcium sulfatedihydrate, and alkali metal citrate investigated in Example 19.

TABLE 68 Compressive Strength of Example 19 - (psi) 4 hour 24 hour 7 day28 day Mix 1 225 555 1586 3707 Mix 2 752 2510 4677 4646 Mix 3 1427 28925128 5191 Mix 4 1862 3737 4886 6084

The following important observations can be drawn from this study:

The compressive strength of the mixture compositions continued toincrease as a function of time.

Both the early age compressive strength and the ultimate compressivestrength of the cementitious compositions with no fine-grained calciumsulfate dihydrate (Mix 1) were lower in comparison to those for thegeopolymer cementitious compositions of this embodiment comprisingfine-grained calcium sulfate dihydrate (Mixes 2 through 4).

The early age (about 4-hour and about 24-hour) compressive strength ofthe geopolymer cementitious compositions of this embodiment increasedsubstantially with increase in the amount of fine-grained calciumsulfate dihydrate in the composition. Comparing the testing results forExample 19, Example 17, and Example 7, it can be concluded that use offine-grained calcium sulfate dihydrate provides a more rapid increase in4-hour material compressive strength.

The 24-hour compressive strength of material was in excess of about 2500psi with the use of fine-grained calcium sulfate dihydrate in thegeopolymer cementitious compositions of this embodiment. Comparing thetesting results for Example 19, Example 17, and Example 7, it can beconcluded that use of fine-grained calcium sulfate dihydrate provides amore rapid increase in the early age material compressive strength.

The 28-day compressive strength of all geopolymer cementitiouscompositions of this embodiment comprising fly ash, calciumsulfoaluminate, fine-grained calcium sulfate dihydrate and sodiumcitrate was relatively high and in excess of about 4500 psi. Moreover,the 28-day compressive strength of the geopolymer mixture compositionsof this embodiment comprising fine-grained calcium sulfate dihydrate atan amount of about 20 wt % and about 30 wt % (Mixes 3 and 4) were againvery high and in excess of about 5000 psi.

Example 20

An objective of this investigation was to study the influence ofincorporation of high purity, fine-grained calcium sulfate dihydrate atvarying amounts, in the geopolymer binder compositions of the invention.

TABLE 69 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisExample was equal to 80 wt % of the weight of fly ash. The fine-grainedcalcium sulfate dihydrate used in this investigation was from USGCompany with the trade name USG Terra Alba F&P. Calcium sulfatedihydrate was added at the following amount levels in the mixturecompositions investigated 40 wt %, 50 wt %, 60 wt % and 80 wt % of theweight of calcium sulfoaluminate cement. The calcium sulfate dihydratewas added at levels of 32, 40, 48, and 64 wt. % of the Class C fly ash.Sodium citrate added to the cementitious compositions of the inventionacted as a chemical activator. The water to cementitious materials ratioutilized in this investigation was kept constant at 0.30. The sand usedis QUIKRETE Commercial Grade Fine Sand No. 1961 and the Superplasticizeris BASF CASTAMENT.

TABLE 69 Geopolymer cementitious compositions of Example 20 Raw MaterialMix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 1415 1364 1316 1230Calcium Sulfate Dihydrate 453 545.5 632 787 (grams) CalciumSulfoaluminate 1132 1091 1053 984 Cement (grams) Total CementitiousMaterials 3000 3000 3000 3000 (grams) Sand (grams) 3150 3150 3150 3150Sodium Citrate Dihydrate 60 60 60 60 (grams) Superplasticizer (grams) 1550 15 15 Water (grams) 900 900 900 900 Water/Cementitious Materials 0.300.30 0.30 0.30 Ratio Sand/Cementitious Materials 1.05 1.05 1.05 1.05Ratio Superplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5% Materials, wt %Sodium Citrate/Cementitious 2.0% 2.0% 2.0% 2.0% Materials, wt % CalciumSulfoaluminate  80%  80%  80%  80% Cement/Fly ash, wt % CalciumSulfate/Calcium  40%  50%  60%  80% Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking Behavior ofMaterial

TABLE 70 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of the embodiment comprisingfly ash, calcium sulfoaluminate cement, fine-grained calcium sulfatedihydrate, and alkali metal citrate in Example 20.

TABLE 70 Flow and Slump of Example 20 Flow Slump (inches) Mix 1 10 10.75Mix 2 10 9.75 Mix 3 10 9.5 Mix 4 10 10

All mixture compositions investigated had good flow behavior and largepatty diameter as observed in the slump test. It is particularlynoteworthy that such large slump and self-leveling behavior wasobtainable even at a water/cementitious materials ratio as low as about0.3.

The slump patties made from Mixes 1-4 were in excellent condition afterdrying and did not develop any cracking. Thus, addition of fine-grainedcalcium sulfate dihydrate to the cementitious mixtures comprisingcalcium sulfoaluminate cement, fly ash, and alkali metal citrateprovides dimensionally stable compositions possessing superiorresistance to cracking upon drying.

Shrinkage Behavior

FIG. 20A shows shrinkage behavior of geopolymer cementitiouscompositions of the embodiment in Example 20.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH. Thefollowing important conclusions can be drawn from this investigation andFIG. 20 c:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate dihydrate) which cracked even before de-molding, the shrinkagebars of Example 20 comprising fine-grained calcium sulfate dihydratewere stable and did not result in any cracks either prior to or afterde-molding.

The geopolymer cementitious compositions of the embodiment comprisingcalcium sulfoaluminate cement and fine-grained calcium sulfate dihydrateinvestigated in this Example had a measured maximum shrinkage of about0.14% to about 0.23% in comparison to a measured maximum shrinkage ofabout 0.75% for the comparative mixture containing fly ash and alkalimetal citrate only (Example 1).

Increase in the fine-grained calcium sulfate dihydrate amount in therange investigated in this Example resulted in an increase in thematerial shrinkage behavior. For instance, at a fine-grained calciumsulfate dihydrate amount of about 40 wt %, the, measured maximummaterial shrinkage was about 0.14%. The measured maximum shrinkageincreased to about 0.23% at a fine-grained calcium sulfate dihydrateamount of about 80 wt %.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 20B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of the embodiment investigated inExample 20. It can be noticed that the cementitious compositions ofExample 20 comprising fly ash, calcium sulfoaluminate cement,fine-grained calcium sulfate dihydrate, and alkali metal citratedemonstrated only a very moderate temperature rise behavior. A moderateheat evolution and low temperature rise within the material during thecuring stage are significantly contributes to preventing excessivethermal expansion and consequent cracking and disruption of material.This aspect is of assistance when the material is utilized in a mannerwhere large thicknesses of material pours are involved in the actualfield applications. The geopolymer cementitious compositions of theembodiment investigated in this Example are disclosed to be highlybeneficial in this particular aspect as they would lead to a lowerthermal expansion and enhanced resistance to thermal cracking in actualfield applications.

Time of Setting

TABLE 71 shows the time of setting of geopolymer cementitiouscompositions of the embodiment in Example 20.

TABLE 71 Setting Times of Example 20 Initial Setting Time (hr:min) FinalSetting Time (hr:min) Mix 1 00:49  1:38 Mix 2 1:08 1:32 Mix 3 1:04 1:30Mix 4 1:11 1:58

All cementitious compositions investigated in this Example demonstratedrapid setting behavior. Also, the final setting times of the geopolymercementitious compositions of this embodiment were about 90 to about 120minutes compared to an extremely rapid final setting time of about 15minutes for the comparative mixture composition containing fly ash andsodium citrate only (Example 1).

Compressive Strength

TABLE 72 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment comprising flyash, calcium sulfoaluminate cement, fine-grained calcium sulfatedihydrate, and alkali metal citrate investigated in Example 20.

TABLE 72 Compressive Strength of Example 20 - (psi) 4 hour 24 hour 7 day28 day Mix 1 2351 4077 5317 7221 Mix 2 2440 4020 5626 7255 Mix 3 22133804 6187 6140 Mix 4 1661 3933 4911 5669

The following important observations can be drawn from this study:

The compressive strength of the mixture compositions investigatedcontinued to increase as a function of time.

The early age (about 4-hours and about 24-hours after mixing)compressive strengths of the geopolymer cementitious compositions ofthis embodiment comprising fine-grained calcium sulfate dihydrateinvestigated in this Example (Mixes 1 through 4) are significantlygreater than those for the comparative mixture composition containing nofine-grained calcium sulfate dehydrate (Mix 1 of Example 19).

The early age/early stage (4-hour and 24-hour after mixing) compressivestrength of the geopolymer cementitious compositions of this embodimentwere very high and remained fairly constant with increase in the amountof fine-grained calcium sulfate dihydrate amount in the composition.

Comparing the testing results for Example 20 and Example 18, it is clearthat use of fine-grained calcium sulfate dihydrate provides a more rapidincrease in 4-hour material compressive strength. For example, it can beobserved that with the use of fine-grained calcium sulfate dihydrate inthe mixture compositions of this example, the 4-hour materialcompressive strengths achieved were in excess of about 2000 psi (Mixes 1through 3 of Example 20). In contrast, the 4-hour compressive strengthsof mixture compositions comprising the same amount levels ofcoarse-grained landplaster were less than about 600 psi as seen forMixes 1 through 3 of Example 18.

The 24-hour compressive strengths of the geopolymer cementitiouscompositions of this embodiment investigated in this Example were inexcess of about 3500 psi with the use of a fine-grained calcium sulfatedihydrate. The use of fine-grained calcium sulfate dihydrate in themixture compositions of Example 20 provided the 24-hour materialcompressive strengths in excess of about 3500 psi (Mixes 1 through 4 ofExample 20); while the mixture compositions containing the same amountlevels of coarse-grained landplaster provided 24-hour compressivestrengths of less than about 2500 psi for Mixes #1 through 4 of Example18.

The 28-day compressive strengths of the geopolymer cementitiouscompositions of the embodiment comprising fly ash, calciumsulfoaluminate, fine-grained calcium sulfate dihydrate and sodiumcitrate investigated in this Example were greater than about 5000 psi.Moreover, for Mixes #1 through 3 of Example 20, the about 28-daycompressive strengths of the material were in excess of about 6000 psi.Comparison of the testing results for Example 20 and Example 18 showsthat the use of fine-grained calcium sulfate dihydrate provides arelatively higher about 28-day material compressive strength. Forinstance, the use of fine-grained calcium sulfate dihydrate in themixture compositions of Example 20, the about 28-day materialcompressive strengths of over about 7,000 psi were achieved.

Example 21

This example studies the influence of incorporation of calciumsulfoaluminate cement at low amounts (about 20 parts by weight of flyash) in combination with calcium sulfate and an alkali metal citrate.

TABLE 73 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example. FASTROCK 500 brandcalcium sulfoaluminate cement, available from CTS Cement Company wasutilized as a component of cementitious reactive powder in thisinvestigation. The amount of calcium sulfoaluminate cement used in themixture compositions of this Example was equal to 0, 5, 10, 15 and 20wt. % of the Class C fly ash. Fine-grained calcium sulfate dihydrate,termed here as landplaster, used in this investigation was procured fromthe United States Gypsum Company. Landplaster was added at an amount of50% of the weight of calcium sulfoaluminate cement in the variousmixture compositions investigated. The landplaster was added in levelsof 0, 2.5, 5, 7.5 and 10 wt. % of the fly ash. The sand used is QUIKRETECommercial Grade Fine Sand No. 1961 and the superplasticizer is BASFCASTAMENT. SURFYNOL 500S surfactant available from Air Products, Inc.was also used as a defoamer and wetting agent.

TABLE 73 Mixture compositions of Example 21 Raw Material Mix 1 Mix 2 Mix3 Mix 4 Mix 5 Fly Ash Class C (grams) 5250 4884 5000 4286 4423 CalciumSulfate Dihydrate 0 122 250 321 442 (grams) Calcium Sulfoaluminate 0 244500 643 885 Cement (grams) Total Cementitious 5250 5250 5750 5250 5750Materials (grams) Sand (grams) 5513 5513 6038 5513 6038 Sodium CitrateDihydrate 105 105 115 105 115 (grams) Superplasticizer (grams) 0 26.2528.75 26.25 28.75 Defoamer & Wetting Agent 10.5 10.5 10.5 10.5 11.5(grams) Water (grams) 1444 1444 1581 1444 1581 Water/Cementitious 0.2750.275 0.275 0.275 0.275 Materials Ratio Sand/Cementitious 1.05 1.05 1.051.05 1.05 Materials Ratio Superplasticizer/Cementitious 0 0.5% 0.5% 0.5%0.5% Materials, wt % Sodium Citrate/Cementitious   2%   2%   2%   2%  2% Materials, wt % Calcium Sulfoaluminate   0%   5%  10%  15%  20%cement/Fly ash, wt % Calcium Sulfate/Calcium   0%  50%  50%  50%  50%Sulfoaluminate Cement, wt %

Initial Flow Behavior, Slump, and Early Age Cracking of Material

TABLE 74 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of the embodiment comprisingfly ash, calcium sulfoaluminate cement, calcium sulfate (fine-grainedlandplaster), and alkali metal citrate investigated in Example 21.

TABLE 74 Flow and Slump of Example 21 Flow Slump (inches) Mix 1 8 8.5Mix 2 10 12 Mix 3 10 12 Mix 4 10 11.5 Mix 5 10 12

All mixture compositions of this embodiment (Mix 2 through 5) had goodself-leveling, flow behavior and large patty diameter as observed in theslump test. It is particularly noteworthy that such large slump andself-leveling behavior was obtainable even at an extremely lowwater/cementitious materials ratio of about 0.275. For standard Portlandcement based or gypsum based materials, such flow properties and selfleveling behavior are only obtainable when the water/cementitiousmaterials ratio is in excess of about 0.45.

The slump patties for the mixture compositions of this embodiment (Mix 2through Mix 5) of this Example did not develop any cracking upon drying.Thus, it can be concluded that incorporation of calcium sulfoaluminatecement and calcium sulfate dihydrate (fine-grained landplaster) even atlow amounts (about 20 wt % of fly ash weight) to the cementitiousmixture comprising fly ash and alkali metal citrate providesdimensionally stable geopolymer cementitious compositions possessingsuperior resistance to cracking upon drying.

Shrinkage Behavior

FIG. 21A shows shrinkage behavior of geopolymer cementitiouscompositions of the embodiment investigated in Example 21. The shrinkagemeasurements were initiated at an age of about 4-hours for Mix 2 throughMix 5 from the time the raw materials were mixed together to form anaqueous slurry. For the comparative Mix 1, the 4-hour shrinkage barsbroke in the molds due to excessive material shrinkage as seen in FIG.21B. The shrinkage data presented in FIG. 21A for the comparative Mix 1represents the very early age material shrinkage behavior for the barsdemolded at an age of about 1 hours with shrinkage measurementsinitiated at the same age. FIG. 21C shows the very early age materialshrinkage for all five mixes demolded at the age of 1-hour withshrinkage measurements initiated at the same time. The materialshrinkage was measured for a total duration of about 8-weeks whilecuring the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIGS. 21A and 21B:

The incorporation of calcium sulfoaluminate cement even at very smallamounts (about 20 wt % of fly ash weight) had a significant impact onimproving the dimensional stability and consequent cracking resistanceof geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfate dihydrate, and alkali metal citrate. Contraryto the 4-hour shrinkage bars of the comparative Mix 1 containing nocalcium sulfoaluminate cement and fine-grained calcium sulfate dihydrate(landplaster) which cracked even before de-molding, the shrinkage barsfor Mix 2 through Mix 5 comprising calcium sulfoaluminate cement andfine-grained calcium sulfate dihydrate (landplaster) were stable and didnot crack either prior to or after de-molding.

The geopolymer cementitious compositions of this embodiment comprisingfly ash, calcium sulfoaluminate cement, fine-grained calcium sulfatedihydrate (landplaster), and alkali metal citrate had a maximumshrinkage of less than about 0.10% in comparison to a maximum shrinkagein excess of about 0.5% for the mixture comprising fly ash and alkalimetal citrate only for the comparative Mix 1 of the Example 21. It isnoteworthy that the maximum recorded shrinkage for Mix 2 comprisingcalcium sulfoaluminate cement at 5 parts was only about 0.07%, while thesame for Mix 3 comprising calcium sulfoaluminate cement at about 10parts was only about 0.05%. Thus, addition of even small amounts ofcalcium sulfoaluminate cement and fine-grained calcium sulfate dihydrate(landplaster) to the cementitious compositions comprising fly ash andalkali metal citrate helps to very significantly reduce the materialshrinkage.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 21D shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions of the embodiment investigated inExample 21. The cementitious compositions of Example 21 comprising flyash, calcium sulfoaluminate cement, fine-grained calcium sulfatedihydrate (landplaster), and alkali metal citrate demonstrated only avery moderate temperature rise behavior. A moderate heat evolution andlow temperature rise within the material during the curing stagesignificantly contributes to preventing excessive thermal expansion andconsequent cracking and disruption of material. This aspect is helpfulwhen the material is utilized in a manner where large thicknesses ofmaterial pours are involved in the actual field applications. Thegeopolymer cementitious compositions of the embodiment investigated inthis Example are highly beneficial in this particular aspect as theywould lead to a lower thermal expansion and enhanced resistance tothermal cracking in actual field applications.

Time of Setting

TABLE 75 shows the time of setting of geopolymer cementitiouscompositions of the embodiment in Example 21.

TABLE 75 Setting Times of Example 21 Initial Setting Time (hr:min:sec)Final Setting Time (hr:min:sec) Mix 1 00:13 00:30 Mix 2 00:35 00:47 Mix3 00:43 00:50 Mix 4 00:38 00:53 Mix 5 00:33  1:00

All cementitious compositions investigated in this example demonstratedvery rapid setting behavior with final setting times of about 45 toabout 60 minutes. It can also be observed that the developedcementitious compositions of this embodiment comprising fly ash, calciumsulfoaluminate cement, fine-grained calcium sulfate dihydrate(landplaster), and alkali metal citrate had relatively longer settingtimes (both initial and final) than the comparative cementitiouscomposition comprising fly ash and alkali metal citrate only (Mix 1 ofExample 21).

Compressive Strength

TABLE 76 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment comprising flyash, calcium sulfoaluminate cement, fine-grained calcium sulfatedihydrate (landplaster), and alkali metal citrate in Example 21.

TABLE 76 Compressive Strength of Example 21 - (psi) 4 hour 24 hour 7 day28 day Mix 1 589 1522 4775 7095 Mix 2 561 1065 2781 4134 Mix 3 800 13842284 5919 Mix 4 1050 1692 2782 4676 Mix 5 1222 2116 3829 4875

The following observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofthe embodiment investigated in this Example continued to increase withtime.

The early age 4-hour compressive strengths of the material were inexcess of about 1000 psi with the use of calcium sulfoaluminate cementand fine-grained calcium sulfate dihydrate (landplaster) as a componentof the geopolymer cementitious compositions of this embodiment.

The early age 24-hour compressive strengths of the material were inexcess of about 2000 psi with the use of calcium sulfoaluminate cementand fine-grained calcium sulfate dihydrate (landplaster) as a componentof the investigated geopolymer cementitious compositions of thisembodiment.

The about 28-day compressive strengths of all geopolymer cementitiouscompositions of this embodiment investigated in this Example were inexcess of about 4000 psi.

Example 22

This example studies the physical properties of the developed geopolymercementitious compositions of this embodiment comprising fly ash, calciumsulfoaluminate cement, fine-grained calcium sulfate activated witheither an alkali metal hydroxide (sodium hydroxide) or a mixture of analkali metal hydroxide (sodium hydroxide) and an alkali metal acid(citric acid).

TABLE 77 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example. The amount ofcalcium sulfoaluminate cement used in the mixture compositions of thisExample was equal to 20 wt % of the weight of fly ash. Landplaster wasadded at an amount of 50% of the weight of calcium sulfoaluminate cementand 10 wt. % of the Class C fly ash, in the various mixture compositionsinvestigated. A mixture of sodium hydroxide and citric acid was added tothe cementitious compositions of the invention to act as a chemicalactivator. Two of the mixes (Mix 2 and Mix 3) investigated containedonly sodium hydroxide as the chemical activator and no citric acid.Similarly, one of the mixes (Mix 1) contained only citric acid forchemical activation and no sodium hydroxide. SURFYNOL 500S surfactantavailable from Air Products, Inc. used as a defoamer and wetting agent.The sand is QUIKRETE Commercial Grade Fine Sand No. 1961 and thesuperplasticizer is BASF CASTAMENT FS20.

TABLE 77 Mixture compositions of Example 22 Raw Material Mix 1 Mix 2 Mix3 Mix 4 Mix 5 Fly Ash Class C (grams) 4039 4039 4039 4039 4039 CalciumSulfate Dihydrate 404 404 404 404 404 (grams) Calcium Sulfoaluminate 808808 808 808 808 Cement (grams) Total Cementitious 5250 5250 5250 52505250 Materials (grams) Sand (grams) 5513 5513 5513 5513 5513 Citric AcidMonohydrate 105 0 0 105 105 (grams) Sodium Hydroxide 0 52.5 157.5 52.5157.5 (grams) Superplasticizer (grams) 26.25 26.25 26.25 26.25 26.25Defoamer & Wetting 10.50 10.50 10.50 10.50 10.50 Agent (grams) Water(grams) 1444 1444 1444 1444 1444 Water/Cementitious 0.275 0.275 0.2750.275 0.275 Materials Ratio Sand/Cementitious 1.05 1.05 1.05 1.05 1.05Materials Ratio Superplasticizer/ 0.5% 0.5% 0.5% 0.5% 0.5% CementitiousMaterials, wt % Calcium Sulfoaluminate  20%  20%  20%  20%  20%cement/Fly ash, wt % Calcium Sulfate/Calcium  10%  10%  10%  10%  10%Sulfoaluminate Cement, wt %

Initial Flow Behavior and Slump

TABLE 78 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of the embodiment investigatedin Example 22.

TABLE 78 Flow and Slump of Example 22 Flow Slump (inches) Mix 1 1 2 Mix2 10 10.5 Mix 3 7 7.25 Mix 4 11 11.75 Mix 5 8 8.25

For Mix 1 containing citric acid but no sodium hydroxide, it was notedthat the mixed material was extremely stiff and completely unworkableupon mixing. On the other hand, mixture compositions containing sodiumhydroxide (Mix 2 and Mix 3) or a blend of sodium hydroxide and citricacid (Mix 4 and Mix 5), were easily workable as also indicated by theirrelatively large patty diameter in the slump test. It is particularlynoteworthy that such good workability was obtainable even at anextremely low water/cementitious materials ratio of about 0.275. Forstandard Portland cement based or gypsum based materials, such flowproperties and self leveling behavior are only obtainable when thewater/cementitious materials ratio is in excess of about 0.45.

Shrinkage Behavior

FIG. 22A shows shrinkage behavior of geopolymer cementitiouscompositions in Example 22.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 22A:

The mixture compositions comprising sodium hydroxide only as a chemicalactivator (Mix 2 and Mix 3) demonstrated a very low shrinkage of aboutless than about 0.1%. It is noteworthy that the maximum shrinkage of Mix2 containing only 1% sodium hydroxide was less than about 0.05%. Themaximum shrinkage increased to about 0.09% for Mix 3 containing sodiumhydroxide at an amount of about 3%.

The cementitious compositions of this embodiment comprising a mixture ofsodium hydroxide and citric acid as a chemical activator (Mix 4 and Mix5) also demonstrated very low shrinkage. The maximum shrinkage of Mix 3containing citric acid and sodium hydroxide at an amount of about 1% wasonly about 0.05%. The maximum shrinkage increased to about 0.25% for Mix5 containing citric acid and sodium hydroxide at an amount of about 3%.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 22B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious compositions in Example 22. The cementitiouscompositions in this Example (Mix 2 through Mix 5) demonstrated very lowincrease in temperature. Mix 1 with only citric acid (and no sodiumhydroxide) stiffened up upon mixing and demonstrated extremely poorreactivity as indicated by the very low temperature rise. A moderateheat evolution and low temperature rise within the material during thecuring stage significantly contribute to preventing excessive thermalexpansion and consequent cracking and disruption of material. Thisaspect is of assistance when the material is utilized in a manner wherelarge thicknesses of material pours are involved in the actual fieldapplications. The geopolymer cementitious compositions of the embodimentinvestigated in this Example are disclosed to be highly beneficial inthis particular aspect as they would lead to a lower thermal expansionand enhanced resistance to thermal cracking in actual fieldapplications.

Time of Setting

TABLE 79 shows the time of setting of geopolymer cementitiouscompositions in Example 22.

TABLE 79 Setting Times of Example 22 Initial Setting Time (hr:min) FinalSetting Time (hr:min) Mix 1 Soft >3 hrs Mix 2 00:31 00:42 Mix 3 00:1000:16 Mix 4 00:47 00:57 Mix 5 00:38 00:43

All cementitious compositions of this embodiment investigated in thisexample (Mix 2 through Mix 5) demonstrated very rapid setting behaviorwith final setting times of about 15 to about 60 minutes. The mixturecompositions comprising sodium hydroxide at an amount level of about 1%(Mix 2 and Mix 4) had relatively longer setting time (and open time) incomparison to mixture compositions comprising sodium hydroxide at anamount of about 3% (i.e., Mix 3 and Mix 4). An extremely short settingtime is problematic for some applications as a short material workinglife (pot life) causes significant difficulties with processing of rapidsetting material in the actual field applications.

Compressive Strength

TABLE 80 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment comprising flyash, calcium sulfoaluminate cement, and calcium sulfate (fine-grainedlandplaster), and alkali metal chemical activators in Example 22.

TABLE 80 Compressive Strength of Example 22 - (psi) 4 hour 24 hour 7 day28 day Mix 1 — — — — Mix 2 1936 2820 4346 6207 Mix 3 1310 1635 4326 6330Mix 4 1343 2143 3971 5516 Mix 5 1593 4270 6887 9513

The following important observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositions ofthe embodiment investigated in this Example continued to increase withtime.

The early age 4-hour compressive strengths of the material were inexcess of about 1000 psi with the use of calcium sulfoaluminate cementand landplaster as a component of the geopolymer cementitiouscompositions of this embodiment. This was true when sodium hydroxide wasused as a chemical activator by itself (Mix 2 and Mix 3) or when amixture of sodium hydroxide and citric acid was used as a chemicalactivator (Mix 4 and Mix 5).

The early age 24-hour compressive strengths of the material were inexcess of about 2000 psi with the use of calcium sulfoaluminate cementand landplaster as a component of the investigated geopolymercementitious compositions of this embodiment. This was true when sodiumhydroxide was used as a chemical activator by itself (Mix 2 and Mix 3)or when a mixture of sodium hydroxide and citric acid was used as achemical activator (Mix 4 and Mix 5).

The 28-day compressive strength of all geopolymer cementitiouscompositions of this embodiment investigated in this Example was inexcess of about 5000 psi. This again was true when sodium hydroxide wasused as a chemical activator by itself (Mix 2 and Mix 3) or when amixture of sodium hydroxide and citric acid was used as a chemicalactivator (Mix 4 and Mix 5).

Example 23

This Example shows the influence of incorporating calcium sulfoaluminatecement at different amounts (20 parts, 40 parts, 60 parts and 80 partsby weight of fly ash) in combination with calcium sulfate dihydrate,which is added at levels of 6, 12, 18 and 24 wt. % of the fly ash, onthe very early age shrinkage behavior of the geopolymer cementitiouscompositions of the invention. The compositions tested are listed inTABLE 81. The sand is QUIKRETE Commercial Grade Fine Sand No. 1961 andthe superplasticizer is BASF CASTAMENT FS20.

TABLE 81 Mixture compositions of the geopolymer cementitious reactivepowder compositions of Example 23 Raw Material Mix 1 Mix 2 Mix 3 Mix 4Fly Ash Class C (grams) 3175 2632 2247 1961 Calcium Sulfate Dihydrate191 312 404.5 471 (grams) Calcium Sulfoaluminate 635 1053 1348 1569Cement (grams) Total Cementitious 4000 4000 4000 4000 Materials (grams)Sand (grams) 4200 4200 4200 4200 Sodium Citrate Dihydrate 80 80 80 80(grams) Superplasticizer (grams) 20 20 20 20 Defoamer & Wetting Agent 00 0 0 (grams) Water (grams) 1200 1200 1200 1200 Water/Cementitious 0.300.30 0.30 0.30 Materials Ratio Sand/Cementitious 1.05 1.05 1.05 1.05Materials Ratio Superplasticizer/Cementitious 0.5% 0.5% 0.5% 0.5%Materials, wt % Sodium   2%   2%   2%   2% Citrate/CementitiousMaterials, wt % Calcium Sulfoaluminate  20%  40%  60%  80% Cement/Flyash, wt % Calcium Sulfate/Calcium  30%  30%  30%  30% SulfoaluminateCement, wt %

Very Early Age Shrinkage Behavior

FIG. 23A shows the very early age shrinkage behavior of geopolymercementitious compositions of the embodiment investigated in Example 23.

The very early age shrinkage testing was conducted as described abovebut the initial measurement was initiated at about 1-hour from the timethe raw materials were mixed together to form an aqueous slurry. Themain objective of this investigation was to study the influence ofincorporation of different amounts of calcium sulfoaluminate cement(about 20 to about 80 parts by weight of fly ash) and fine-grainedcalcium sulfate dihydrate on the very early shrinkage behavior of thegeopolymer cementitious compositions of this embodiment.

From FIG. 23A and Table 82 it can be observed that the magnitude of veryearly age shrinkage increased with increase in the amount of calciumsulfoaluminate cement in the compositions of this embodiment. This was ahighly unexpected result.

TABLE 82 summarizes the percentage of shrinkage for bars made using themixes in Example 23, as shown in FIG. 23A.

TABLE 82 parts of Very Early Age Shrinkage of Example 23 calcium(percentage) sulfoaluminate 4 hour final 8 hour final 24 hour finalcement in Mix measurement measurement measurement Mix 1 20 0.02 0.030.05 Mix 2 40 0.06 0.08 0.09 Mix 3 60 0.09 0.12 0.13 Mix 4 80 0.13 0.160.17

The aforementioned results represent an extremely important aspect ofthe present invention. These results are highly unexpected and depictthe very early age shrinkage of the cementitious compositions of thisembodiment which increases with increasing amount of calciumsulfoaluminate cement in the composition. These results suggest it isbeneficial to keep the amount of calcium sulfoaluminate cement in thecompositions of this and related embodiments relatively low (preferablyabout 20 parts or lower) if the primary objective of the application isto minimize the magnitude of very early age shrinkage and totalshrinkage of the material. Although the reasons for the very earlyshrinkage of the material observed here are not completely understood,it is believed that the early shrinkage is attributable to the chemicaland autogenous shrinkage resulting from the self-desiccation andvolumetric changes of the reactant materials.

Another major benefit of keeping the amounts of calcium sulfoaluminatecement and calcium sulfate low in the compositions of this embodimentand related embodiments is significantly reduced potential forefflorescence. It should be noted that a high degree of efflorescence inthe material not only presents an aesthetic problem but it can also leadto material disruption and damage at later ages due to expansivereactions that can occur due to the chemical and hydration reactions ofthe salts present in the hardened material.

Another major benefit of keeping the amounts of calcium sulfoaluminatecement and calcium sulfate low in the compositions of this embodiment isthat it significantly reduces the cost of raw materials.

Example 24

This example depicts tensile bond strength performance of fly ash,calcium sulfoaluminate cement, fine-grained calcium sulfate dihydrate(i.e., gypsum or landplaster) and an alkali metal salt. In total, fourmixture compositions were investigated.

In TABLE 83, Mix 1 represents a geopolymer cementitious composition ofthe invention containing no film-forming redispersible polymer powder.On the other hand, Mix 2 through Mix 4 represent geopolymer cementitiouscompositions of the invention containing film-forming redispersiblepolymer powder added at different amount levels. Film-formingredispersible polymer powder with commercial trade name VINNAPAS 5025L(Vinyl Acetate/Ethylene Copolymer) produced by WACKER Polymers was usedin the last three mixture compositions. Quickrete Commercial Grade FineSand No. 1961 was used along with BASF CASTAMENT FS20 superplasticizerand SURFYNOL 500S defoamer available from Air Products Inc.

TABLE 83 Mixture compositions of Example 24 Raw Material Mix 1 Mix 2 Mix3 Mix 4 Fly Ash Class C (grams) 4039 4039 4423 4039 Calcium SulfateDihydrate (grams) 404 404 442 404 Calcium Sulfoaluminate Cement 808 808885 808 (grams) Total Cementitious Materials (grams) 5250 5250 5750 5250Sand (grams) 5513 5513 6033 5513 Sodium Citrate Dihydrate (grams) 105105 115 105 Superplasticizer (grams) 26.25 26.25 28.75 26.25 Defoamer &Wetting Agent 10.5 10.5 11.5 10.5 Redispersible Polymer Powder 0.0 26.2557.5 78.75 (grams) Water (grams) 1444 1444 1581 1444 Water/CementitiousMaterials Ratio 0.275 0.275 0.275 0.275 Sand/Cementitious MaterialsRatio 1.05 1.05 1.05 1.05 Superplasticizer/Cementitious 0.5% 0.5% 0.5%0.5% Materials, wt % Sodium Citrate/Cementitious   2%   2%   2%   2%Materials, wt % Calcium Sulfoaluminate cement/Fly  20%  20%  20%  20%ash, wt % Calcium Sulfate/Calcium  30%  30%  30%  30% SulfoaluminateCement, wt %

Tensile Bond Strength

Tensile bond strength between Portland cement based mortar substrate andgeopolymer cementitious compositions as mentioned in Table 102 wasinvestigated. Approx. 2 in.×2 in.×2 in. cube molds were first filled tohalf the thickness (1″) with Portland cement based mortar. The materialwas allowed to cure and harden in sealed plastic bags for at least about28-days after the cast. After the completion of about 28-day curing, thetop surface of the Portland cement mortar was then primed with anacrylic primer. Subsequently, geopolymer cementitious compositions ofthis embodiment per Table 84 were poured in the molds up to the topsurface. The top surface of the freshly placed material was screeded tocreate a flat surface. The specimens were then allowed to cure until thetime of testing. After the completion of curing, the test specimen weredemolded and approx. 2 in×2 in. steel anchor blocks were epoxy bonded toboth the top and bottom surfaces of the specimen. The specimens werethen pulled in tension in a suitable testing frame (MTS Testing Machine)and the ultimate failure load was recorded. The failure stress wascalculated by dividing the failure load by the bonded surface areabetween the Portland cement mortar substrate and the geopolymercementitious material. For each mix investigated in this Example, fivesamples were tested to failure.

TABLE 84 shows the average tensile bond strength of the four geopolymermixture compositions investigated in this Example. All specimens werecured for 8 days and tested for tensile bond strength. It can beobserved that all four mixture compositions investigated had extremelyhigh tensile bond strength. It is particularly noteworthy that thetensile bond strength exceeded about 200 psi for all four geopolymercementitious compositions of this invention investigated in thisExample.

TABLE 84 Tensile bond strength ofgeopolymer cementitious compositions ofthis embodiment Average Tensile Bond Strength Mix Identification (psi)Mix #1 298 Mix #2 239 Mix #3 233 Mix #4 277

The tensile bond strength of the geopolymer cementitious compositionwithout any redispersible polymer powder (Mix 1) was extremelyhigh—about 298 psi. This was a highly unexpected result as such hightensile bond strengths are not typically achievable with othercommercially available Portland cement based materials and products inabsence of polymers. It is notable that addition of redispersiblepolymer powder (Mixes 2 through 4) to the geopolymer cementitiouscompositions of this embodiment did not result in any substantial changeor increase in the tensile bond strength. This result demonstrates avery important aspect of the compositions of the present invention thatredispersible polymer powders are not necessarily required in thegeopolymer cementitious compositions of this embodiment for increasingtheir tensile bond strength to other substrates. Tensile bond strengthis an extremely useful property when the material is used in repairapplications to bond to other substrates. The quality of bond ultimatelydetermines how durable and lasting the repair work will be both in theshort-term and long-term. Poor bond with substrate can result indelamination, cracking, and other modes of failure.

The aforementioned results represent an extremely important aspect ofthe present invention as they depict that to achieve satisfactory bondstrength performance, expensive polymers can be optionally eliminatedfrom the geopolymer compositions of this embodiment. This makes thegeopolymer cementitious compositions of this embodiment unique andextremely cost competitive to the other commercially availablecementitious repair products based on other inorganic bindertechnologies.

Additional tensile bond strength tests were conducted using geopolymercompositions of this embodiment containing other types of redispersiblepolymer powders such as acrylic, styrene acrylate copolymer,styrene-butadiene copolymer, and other. The tensile bond strengthresults for these compositions were extremely high and similar to theresults as reported in this Example above.

Example 25

This example depicts physical properties of the developed geopolymercementitious compositions of this embodiment comprising fly ash, calciumsulfoaluminate cement, fine-grained anhydrite and alkali metal citrate.One main objective of this investigation was to study the influence ofincorporation of calcium sulfoaluminate cement at low amounts ≦about 40parts by weight of fly ash) in combination with fine grained anhydriteon compressive strength behavior of geopolymer compositions of thisembodiment.

The amount of calcium sulfoaluminate cement used in the mixturecompositions of this example was equal to 5, 10, 20, 30 and 40 wt % ofthe weight of fly ash. USG SNOW WHITE filler, a fine-grained anhydrouscalcium sulfate (anhydrite) was used in this investigation. SNOW WHITEfiller was added at an amount of 50% of the weight of calciumsulfoaluminate cement in the various mixture compositions investigated.The anhydrite was added at levels of 2.5, 5, 10, 15 and 20 wt % of theClass C fly ash. QUIKRETE Commercial Grade Fine Sand No. 1961, BASFCASTAMENT FS20 superplasticizer, SURFYNOL 500S defoamer and wettingagent from Air Products, Inc. and AXILAT RH 200 XP succinoglycanhydrocolloid available from Momentive Specialty Chemicals. TABLE 85shows the compositions tested in this example.

TABLE 8 Geopolymer cementitious reactive powder compositions of Example25 in parts by weight Raw Material Mix 1 Mix 1 Mix 3 Mix 4 Mix 5 Fly AshClass C 4419 4130 3846 3276 2969 Anhydrite 111 207 385 491 594 CalciumSulfoaluminate 221 413 769 983 1188 Cement Total Cementitious 4750 47505000 4750 4750 Materials (grams) Sand 5938 5938 6250 5938 5938 SodiumCitrate Dihydrate 95 95 100 95 95 Citric Acid Monohydrate 35.6 35.6 37.535.6 35.6 Superplasticizer 11.9 11.9 12.5 11.9 11.9 Defoamer & WettingAgent⁶ 9.5 9.5 10 9.5 9.5 Rheology Modifier 0.36 0.36 0.38 0.36 0.36Water 1188 1188 1250 1188 1188 Water/Cementitious 0.25 0.25 0.25 0.250.25 Materials Ratio Sand/Cementitious 1.25 1.25 1.25 1.25 1.25Materials Ratio Superplasticizer/ 0.25% 0.25% 0.25% 0.25% 0.25%Cementitious Materials, wt % Sodium Citrate/   2%   2%   2%   2%   2%Cementitious Materials, wt % Calcium Sulfoaluminate  5%  10%  20%  30% 40% cement/Fly ash, wt % Calcium Sulfate/Calcium  50%  50%  50%  50% 50% Sulfoaluminate Cement, wt %

Compressive Strength and Time of Setting

TABLE 86 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of the embodiment comprising flyash, calcium sulfoaluminate cement, fine-grained anhydrite, and alkalimetal citrate investigated in Example 25.

TABLE 86 Compressive Strength of Example 25 - (psi) 28 days + 7 4 hour24 hour 7 day 28 day days saturated Mix 1 1532 2173 5343 7002 6457 Mix 22251 2891 5622 8293 5097 Mix 3 3043 5043 5752 8499 7794 Mix 4 3748 62086965 7239 6880 Mix 5 4386 6563 8826 9273 9299

The compressive strengths of the geopolymer cementitious compositions ofthe embodiment comprising anhydrite as obtained in this Example aresignificantly greater in comparison to similar compositions (ashighlighted in previous examples) containing calcium sulfate dihydrate.This demonstrates the unexpected benefits of using insoluble anhydrouscalcium sulfate (anhydrite or dead burnt anhydrite) compared to calciumsulfate dihydrate discussed in the description of the invention.

The early age 4-hour compressive strengths of the material were inexcess of about 1500 psi for Mix #1 and Mix #2 containing calciumsulfoaluminate cement and anhydrite at lower amounts; and in excess ofabout 3000 psi for Mixes 3 through 5 containing calcium sulfoaluminatecement and anhydrite at higher amounts.

The early age 24-hour compressive strengths of the material were inexcess of about 2000 psi for Mix 1 and Mix 2 containing calciumsulfoaluminate cement and anhydrite at lower amounts; and in excess ofabout 5000 psi for Mixes 3 through 5 containing calcium sulfoaluminatecement and anhydrite at higher amounts.

The 28-day compressive strength of all geopolymer cementitiouscompositions of this embodiment containing calcium sulfoaluminate cementand anhydrite investigated in this example exceeded about 7000 psi.

It was further noted that the geopolymer cementitious compositions ofthis embodiment comprising anhydrite produced relatively faster set incomparison to similar compositions (as highlighted in previous examples)containing calcium sulfate dihydrate. The final set times for the fivemixture compositions investigated in this Example ranged between about25 to about 35 minutes.

The geopolymer cementitious compositions of this invention containinganhydrite as highlighted in the present example are particularly usefulin applications where rapid set and rapid strength development are anessential requirement.

Example 26

This example depicts a geopolymer cementitious composition of thepresent invention particularly useful for use as a self-leveling floorunderlayment over a variety of substrates such as concrete, wood, etc.In particular, compositions similar to the one described in this Exampleare highly useful for smoothening and leveling existing concretesurfaces that are rough and non-planar.

TABLE 87 shows the material composition of this embodiment that was usedover an existing concrete slab to create a smooth surface.

TABLE 87 Compositions of Example 26 Weight Raw Material Parts (grams)Fly Ash Class C¹ 100 8367 Calcium Sulfate Dihydrate² 10 837 CalciumSulfoaluminate Cement³ 20 1673 Total Cementitious Materials 130 10877Sand⁴ 11421 Sodium Citrate Dihydrate 217.5 Citric Acid Anhydrous 54Superplasticizer⁵ 54 Defoamer & Wetting Agent⁶ 22 Rheology Modifier⁷0.87 Smectite Clay⁸ 16.3 Water 2991 Water/Cementitious Materials Ratio0.275 Sand/Cementitious Materials Ratio 1.0Superplasticizer/Cementitious Materials, wt % 0.5% SodiumCitrate/Cementitious Materials, wt %   2% Calcium Sulfoaluminatecement/Fly ash, wt %  20% Calcium Sulfate/Calcium Sulfoaluminate Cement, 50% wt % ¹Class C Fly Ash, Campbell Power Plant, West Olive, MI ²USGLandplaster ³FASTROCK 500, CTS Company ⁴UNIMIN 5030 Sand ⁵BASF CASTAMENTFS20 ⁶SURFYNOL 500S ⁷MOMENTIVE AXILAT RH 100 XP ⁸BENTONE CT HECTORITEclay

The size of the concrete slab over which the geopolymer topping materialwas poured was about 22 ft. ×about 11.5 ft. in area. The surface of theslab was first broomed to remove the dust and debris adhering to theslab surface. This was followed by priming the surface of the slab usingan acrylic floor primer. The materials shown in Table 87 were mixed in adrum using a hand drill mixer. Two batches of the size mentioned inTable 26 were mixed at once in a mixing drum using a hand drill mixer.The water was first poured in the mixing drum following by addition ofthe dry powder blend. The material mixing time was about 2 to about 3minutes to achieve lump free geopolymer slurry of this embodiment. Themixing drum was then transported to the pour area and the geopolymerslurry was poured over the concrete slab. The mixing process asdescribed above was repeated 13 times to obtain enough slurry to coverthe entire concrete slab pour area. The geopolymer slurry flowed andleveled extremely easily. A screed was used to further facilitate andmove the material in the pour area.

The surface of the poured material was then troweled using a steeltrowel to create a flat and smooth surface. The effective thickness ofthe poured material ranged from about 1 inch to featheredge (about 1/16in.) depending upon the location on the slab. The effective thickness ofthe poured material on the slab was measured at the time the materialwas poured over the slab and then re-measured after about 2 hours. Thethickness measurements remained essentially the same from the time ofpouring and after about 2 hours. The total length of the feather edgedmaterial in the pour area was about 22 feet. It is noteworthy that thepoured material featheredged extremely easily. The bond between thefeatheredged material and substrate was found to be exceptional withinabout 2-hours of the pour. It is noteworthy that no cracking ordelamination occurred at the featheredge when the masking tape at theend of the featheredge area was pulled at the age of about 2-hours. Theslab surface was dry and walkable within about 2-hours after the pour.The floor remained substantially crack and defect free until the time oflast inspection that was made after several months after the pour.

The surface pH of the geopolymer binder floor topping surface wasmeasured according to the ASTM F710-11 test method at various timeintervals. The Extech PH150-C Exstick Concrete pH meter was used toconduct the surface pH measurements. Table 88 shows the measured pHvalues of the floor topping surface:

TABLE 88 Surface pH of geopolymer floor topping of Example 26 atdifferent ages after the pour Floor Age pH 16 Hours 10.4 48 Hours 9.9  1Week 9.7  4 Weeks 9.7

The dimensionally stable geopolymer binders of this embodiment owing totheir relatively low pH are highly compatible with the most commerciallyavailable flooring-good adhesives such as acrylic and rubber adhesives.Due to the low pH environment provided by the dimensionally stablegeopolymer binder of this embodiment, the flooring adhesives do notevidence significant chemical breakdowns and instability caused byadverse reactions with the geopolymer composition. As a result, theflooring materials such as sheet vinyl, vinyl composition tiles (VCTs)and carpet can be successfully installed over the dimensionally stablegeopolymer binders of this embodiment to ensure a long lasting anddurable performance.

The tensile bond strength of the applied geopolymer topping to theconcrete substrate was measured according to the ASTM C1583 (2004) testmethod at the age of six weeks. The measured tensile strength valueswere in excess of about 300 psi demonstrating development of excellentbond of the geopolymer topping material to the concrete substrate.

When used as a repair or self-leveling topping material, thedimensionally stable geopolymer compositions of some embodiments of theinvention require minimal substrate preparation for successfulinstallation. Time consuming and expensive substrate preparation methodssuch as shot-blasting, scarifying, water jetting, scabbing or milling tomake the surface ready for installation of the self-leveling geopolymerbinder topping on an existing substrate can be minimized or avoidedaltogether, depending on the application. The geopolymer topping caneither be poured directly over a substrate free of dust and debris, oralternatively, it can be poured over a substrate that has beenappropriately primed using a suitable floor primer.

The cementitious composition can be spread on a surface of a substrate,wherein the cementitious binder is self-leveling and is poured to aneffective thickness of about 0.02 to about 7.5 cm. When used as patchingrepair material or self-leveling topping material over an existingsubstrate, the dimensionally stable geopolymer compositions of someembodiments of the invention are capable of being easily applied toextremely small thicknesses from skim-coating to featheredging.Skim-coating and featheredging here refers to an applied materialthickness of less than about ¼ inch (0.635 cm) and more preferablyranging between about ⅛ inch to about 1/128 inch (0.32 cm to 0.02 cm).

The dimensionally stable geopolymer compositions of some preferredembodiments of the invention are capable of developing exceptionaltensile bond strength with the underlying substrate. The preferabletensile bond strength between the geopolymer material of the inventionand concrete substrate preferably exceeds about 200 psi (1.4 MPa) andmost preferably exceeds about 300 psi (2.1 MPa).

Important distinctive aspects of the geopolymer binder compositions ofthe present invention as highlighted from this Example are as follows:

Extremely low mixing energy requirement to achieve well mixed geopolymerbinder material even with the use of low RPM drill mixers. It isparticularly noteworthy that the geopolymer material of this embodimentis extremely easy to mix despite the use of extremely small amounts ofwater in the formulation. The commonly available cementitiousformulations available in the industry use about twice the amount ofwater to facilitate mixing and produce a workable and self-levelingslurry mixture.

Minimal substrate preparation requirement to accomplish a successfulpour using the geopolymer binder topping materials of this embodiment.There is no need to employ time consuming and expensive substratepreparation methods such as shot-blasting, scarifying, water jetting,scabbing or milling to make the surface ready for the pour. Thegeopolymer material can either be poured directly over a substrate thatis free of dust and debris, or alternatively, it can be poured over asubstrate that has been properly primed using a suitable floor primer.

Ability of the geopolymer binder material of this embodiment to befeatheredged.

Exceptional bond between the geopolymer binder topping of thisembodiment and the concrete substrate.

Geopolymer binder topping material of this embodiment is walkable withinabout 2 hours after the pour.

Extremely high resistance of the geopolymer binder topping of thisembodiment to distress such as delamination and cracking.

Ability of the geopolymer binder material of this embodiment to bepoured to different thicknesses.

Ability of the geopolymer binder material to accept different types ofcoatings on the surface.

Ability of the geopolymer binder topping material to be mixed withcommercially available continuous mortar mixers and other types ofconcrete and mortar batch mixers.

Example 27

TABLE 89 shows the raw material compositions of the cementitiousmixtures investigated in this example.

The amount of calcium sulfoaluminate cement used in the mixturecompositions of this Example was equal to 25 wt % of the weight of flyash. Fine-grained calcium sulfate dihydrate (fine-grained landplaster)used in this investigation was added at a level of 50 wt % of the weightof calcium sulfoaluminate cement, which is 12.5 wt % of the Class C flyash. The Portland cement was added at levels of 25, 67, 150 and 400 wt %of the fly ash, which is approximate rates of 15 wt %, 33 wt %, 52 wt %,and 74 wt % of the total cementitious materials, respectively. The totalcementitious materials include Class C fly ash, calcium sulfatedihydrate, calcium sulfoaluminate and the Portland cement. The water tototal cementitious materials ratio was kept constant at about 0.3 forall mixes investigated. The St. Mary's Type III Portland Cement,Detroit, Mich. was added. QUIKRETE Commercial Grade Fine Sand No. 1961and BASF CASTAMENT FS20 superplasticizer were also used.

TABLE 89 Geopolymer cementitious compositions of Example 27 Raw MaterialMix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 2923 1959 1391 744Calcium Sulfate Dihydrate (grams) 365 245 174 93 Calcium SulfoaluminateCement 731 490 348 186 (grams) Portland Cement Type III(grams) 731 13062087 2977 Total Cementitious Materials 4750 4000 4000 4000 (grams) Sand(grams) 4750 4000 4000 4000 Sodium Citrate Dihydrate (grams) 87.7 58.841.7 22.3 Superplasticizer (grams) 23.75 20 20 20 Water (grams) 14251200 1200 1200 Water/Cementitious Materials Ratio 0.30 0.30 0.30 0.30Sand/Cementitious Materials Ratio 1.0 1.0 1.0 1.0Superplasticizer/Cementitious 0.5%  0.5%  0.5%  0.5%  Materials, wt %Sodium Citrate/Fly Ash, wt %  3%  3%  3%  3% Calcium Sulfoaluminatecement/Fly 25% 25% 25.%  25.%  ash, wt % Calcium Sulfate/Calcium 50% 50%50% 50% Sulfoaluminate Cement, wt % Portland Cement/Cementitious 15% 33%52% 74% Materials, wt %

Initial Flow Behavior and Slump

TABLE 90 shows the initial flow behavior and slump characteristics ofthe cementitious compositions comprising fly ash, calcium sulfoaluminatecement, Landplaster, Portland cement, and alkali metal citrateinvestigated in Example 27.

TABLE 90 Flow and Slump of Example 27 Flow Slump (inches) Mix 1 7 7 Mix2 6 5.5 Mix 3 5 5 Mix 4 4 4.5

All mixture compositions investigated had poor flow behavior asindicated by the stiff slurry and small patty diameter observed in theslump test. The flow properties of the material diminished with increasein the Portland cement in the compositions.

The stiff and high viscous nature of the slump patties is also apparentfrom the slump values in TABLE 90. The slurry mixtures became moreviscous with increase in the Portland cement in the compositions.

Shrinkage Behavior

FIG. 24 shows shrinkage behavior of geopolymer cementitious compositionsof the embodiment investigated in Example 27. The shrinkage measurementswere initiated at an age of about 2⅕ hours from the time the rawmaterials were mixed together to form an aqueous slurry. The materialshrinkage was measured for a total duration of about 8-weeks whilecuring the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 24:

Incorporation of Portland cement significantly increased the shrinkageof the cementitious compositions investigated. The ultimate shrinkagevalues for the various mixes investigated are tabulated in Table 91. Itcan be observed that the ultimate shrinkage for the Mix #1 containingabout 15% Portland cement was about 0.15%. The ultimate shrinkageincreased to about 0.23% for the Mix #2 containing about 33% Portlandcement. The ultimate shrinkage increased to about 0.3% for the Mix #3containing about 50% Portland cement. Finally, for the Mix #4 with about75% Portland cement, the measured shrinkage was the highest at about0.5%.

TABLE 91 Ultimate shrinkage values for the mixture compositionsinvestigated at the age of about 8 weeks Ultimate shrinkage at MixIdentification the age of 8 weeks (%) Mix 1 0.15% Mix 2 0.23% Mix 30.31% Mix 4 0.48%

As discussed in detail on the above description, this example shows theunexpected result obtained with addition of Portland cement toembodiments of the present invention were the Portland cement has anegative influence on the shrinkage behavior of the compositions. Themagnitude of shrinkage is shown by this example to increaseproportionately with increase in the amount of Portland cement in thecompositions.

The addition of Portland cement to cementitious compositions toembodiments of the invention comprising fly ash, calcium sulfoaluminatecement, calcium sulfate and alkali metal citrate very significantlyincreasing the material shrinkage.

Based on the aforementioned findings, addition of Portland cement in thedimensionally stable geopolymer compositions of embodiments of thepresent invention is not recommended.

Example 28

TABLE 92 shows the raw material compositions of the cementitiousmixtures in this example.

The amount of calcium sulfoaluminate cement used in the mixturecompositions of this Example was equal to 20 wt % of the weight of flyash. Fine-grained calcium sulfate dihydrate (fine-grained landplaster)used in this investigation was added at an amount level of 50 wt % ofthe weight of calcium sulfoaluminate cement and 10 wt % of the Class Cfly ash. Mix 1 composition was free of borax, whereas Mixes 2 through 4compositions contained borax as a set control chemical additive.QUIKRETE Commercial Grade Fine Sand No. 1961, BASF CASTAMENT FS20superplasticizer, WACKER Vinnapas 5025L, (Wacker Polymers) and Surfynol500S defoamer from Air Products.

TABLE 92 Geopolymer cementitious compositions of Example 28 Raw MaterialMix 1 Mix 2 Mix 3 Mix 4 Fly Ash Class C (grams) 4039 4039 4039 4039Calcium Sulfate Dihydrate (grams) 404 404 404 404 Calcium SulfoaluminateCement 808 808 808 808 (grams) Total Cementitious Materials 5250 52505250 5250 (grams) Sand (grams) 5513 5513 5513 5513 Sodium CitrateDihydrate (grams) 105 105 105 105 Superplasticizer (grams) 26.25 26.2526.25 26.25 Borax (grams) 0.0 39.4 39.4 52.5 Film Forming RedispersiblePolymer 0.0 26.25 26.25 0.0 Powder⁶ (grams) Defoamer⁷ (grams) 5.25 5.255.25 5.25 Water (grams) 1575 1575 1575 1575 Water/Cementitious MaterialsRatio 0.30 0.30 0.30 0.30 Sand/Cementitious Materials Ratio 1.05 1.051.05 1.05 Superplasticizer/Cementitious 0.5%   0.5% 0.5% 0.5% Materials,wt % Sodium Citrate/Cementitious 2%   2%   2%   2% Materials, wt %Calcium Sulfoaluminate cement/Fly 20%   20%  20%  20% ash, wt % CalciumSulfate/Calcium 50%   50%  50%  50% Sulfoaluminate Cement, wt %Borax/Cementitious Materials, wt % 0% 0.75%  0.75%  1.0% Film-FormingRedispersible Polymer 0% 0.5% 0.5%   0% Powder/Cementitious Materials,wt % Defoamer/Cementitious Materials, 0.1%   0.1% 0.1% 0.1% wt %

Efflorescence Behavior

FIG. 25 shows the photographs of the cubes cast in the brass cube moldsfor the mixes investigated in this example. The top surface of the castcubes is visible in the photographs shown in the figure. It can beobserved that the mixes with borax (Mixes #2, #3 and #4) showedexcessive efflorescence on the top surface of the cubes caused byleaching of the salts from within the material. Whereas, the cubes forMix #1 with no borax were essentially free of efflorescence. Excessiveefflorescence can led to poor aesthetics, material disruption and damagefrom expansive reactions occurring due to the hydration of salts, andreduction in bond strength with other substrates and surface coatings.

Bond Behavior

The dimensionally stable geopolymer binder compositions in accordancewith this invention with borax, borate or boric acid added as anadditional component have also been found to develop poor bond withother materials and substrates such as concrete. Thus, preferably thepresent composition does not include borax, borate or boric acid.

Example 29 Class C Fly Ash Plus Low Lime Calcium Aluminosilicate Mineral(Class F Fly Ash)

TABLE 93 shows the raw material compositions of the geopolymercementitious mixtures investigated in this example.

This example investigated influence of incorporation of low lime calciumaluminosilicate mineral (Class F Fly Ash from Headwaters Resources) incombination with Class C Fly Ash on the physical properties of thegeopolymer compositions of the invention. The Class C fly ash was addedin 76, 38, 18 and 76 parts by weight while Fly Ash F was added at 38 and58 parts by weight in Mixes 2 and 3 were Class C fly ash is added atlevels of 38 and 18 parts by weight, respectively. The calcium sulfatedihydrate was added at 8 parts by weight and the calcium sulfoaluminatewas added at a level of 16 parts by weight. QUIKRETE Commercial GradeFine Sand No. 1961, BASF CASTAMENT FS20 superplasticizer and Surfynol500S defoamer were also added.

TABLE 93 compositions investigated in Example 29 Raw Material Mix #1 Mix2 Mix 3 Mix 4 Fly Ash Class C (grams) 3420 1710 810 0 Calcium SulfateDihydrate (grams) 360 360 360 360 Calcium Sulfoaluminate Cement (grams)720 720 720 720 Fly Ash Class F (grams) 0 1710 2610 3420 TotalCementitious Materials (grams) 4500 5000 4500 4500 Sand (grams) 47254725 4725 4725 Sodium Citrate Dihydrate 90 90 90 90 Superplasticizer(grams) 22.5 22.5 22.5 22.5 Defoaming Agent (grams) 9 9 9 9 Water(grams) 1080 1080 1080 1080 Water/Cementitious Materials Ratio 0.24 0.240.24 0.24 Class F Fly Ash/Total Fly Ash, wt %  0% 50% 76% 100% Superplasticizer/Cementitious 0.5%  0.5%  0.5%  0.5%  Materials, wt %Sodium Citrate/Cementitious  2%  2%  2%  2% Materials, wt % CalciumSulfoaluminate cement/Total 21% 21% 21% 21% Fly ash, wt % CalciumSulfate/Calcium 50% 50% 50% 50% Sulfoaluminate Cement, wt %

Slump and Flow Behavior of Material

TABLE 94 shows the initial flow behavior and slump characteristics ofthe geopolymer cementitious compositions of the embodiment investigatedin Example 29.

TABLE 94 Flow and Slump of Example 29 Flow Slump (inches) Mix 1 10 10.75Mix 2 10 10.25 Mix 3 10 10 Mix 4 10 10.50

All mixture compositions investigated had good rheology and slumpbehavior as observed in the slump test. It is particularly noteworthythat such good rheology and slump behavior was obtainable even at awater/cementitious materials ratio as low as about 0.24.

Shrinkage Behavior

FIG. 26 shows shrinkage behavior of geopolymer cementitious compositionsof the embodiment investigated in Example 29. The main objective of thisinvestigation was to study the influence of incorporation of thermallyactivated aluminosilicate mineral with low lime content (Class F FlyAsh) on shrinkage behavior of the developed geopolymer cementitiouscompositions of this embodiment.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following conclusions can be drawn from this investigation and FIG.26:

The material shrinkage was lowest when the composition contain only thethermally activated aluminosilicate mineral with high lime content,i.e., Class C Fly Ash (Mix #1)

The material shrinkage increased with increase in the amount of low limecontent thermally activated aluminosilicate mineral in the composition.The total shrinkage for Mix 1 in absence of low lime content thermallyactivated aluminosilicate mineral with was about 0.04%. It can beobserved that the total shrinkage for Mix 2 with about 50% low limecontent thermally activated aluminosilicate mineral in the compositionincreased to about 0.07%. The total material shrinkage for Mix 3increased to about 0.1% with about 76% low lime content thermallyactivated aluminosilicate mineral in the composition. The total materialshrinkage for Mix 4 with about 100% low lime content thermally activatedaluminosilicate mineral in the composition was significantly higher atabout 0.18%.

Time of Setting

TABLE 95 shows the time of setting of geopolymer cementitiouscompositions of the embodiment in Example 29.

TABLE 95 Approx. Setting Times of Example 29 Initial Setting Time FinalSetting Time (hr:min) (hr:min) Mix 1 00:23 00:35 Mix 2 00:38 00:52 Mix 300:53 01:22 Mix 4 01:23 02:11

It is observed that both initial and final setting times of thecompositions investigated in this Example increased with increase in theamount of low lime content thermally activated aluminosilicate mineralin the formulation. It can be observed that the final setting time forMix 4 containing about 100% low lime content thermally activatedaluminosiilcate mineral increased significantly to more than about 2hours.

Compressive Strength

TABLE 96 shows the compressive strength behavior of the developedgeopolymer cementitious compositions of this embodiment in Example 29.

TABLE 96 Compressive Strength of Example 29 - (psi) 4 hour 24 hour 7 day28 day Mix 1 2148 3111 5004 7579 Mix 2 1469 2784 3709 4418 Mix 3 8882123 2284 2394 Mix 4 280 1628 1798 1843

The following observations can be drawn from this study:

The compressive strength of the geopolymer cementitious compositionscomprising a mixture of both high and low lime content thermallyactivated aluminosilicate minerals continued to increase as a functionof time.

Both the early age compressive strength and the ultimate compressivestrength of the mixture compositions decreased with increase in theamount of low lime content aluminosilicate mineral in the composition.

Both the early age compressive strength and the ultimate compressivestrength for Mix 2 containing about 50% low lime content aluminosilicatemineral in the composition were satisfactory with the 28 day compressivestrength being in excess of about 4200 psi.

Both the early age and ultimate compressive strengths for Mix 4containing about 100% low lime aluminosiilcate mineral in thecomposition were relatively low and not satisfactory for many of theapplications contemplated as part of this invention.

Example 30

This example depicts a geopolymer cementitious composition of thepresent invention particularly useful for use as a self-leveling floorunderlayment over a variety of substrates such as concrete, wood, etc.In particular, compositions similar to the one described in this exampleare particularly useful for smoothing and leveling existing concretesurfaces that are rough and non-planar.

TABLE 97 shows the material composition of this embodiment:

TABLE 97 Compositions of Example 30 Raw Material Weight (grams) Fly AshClass C¹ 2115 Calcium Sulfate Dihydrate² 212 Calcium SulfoaluminateCement³ 423 Total Cementitious Materials 2750 Sand⁴ 3163 PotassiumCitrate Tribasic Monohydrate 55.0 Citric Acid Anhydrous 13.8 SodiumGluconate 7.44 Superplasticizer⁵ 13.8 Defoamer & Wetting Agent⁶ 5.5Rheology Modifier⁷ 0.11 Smectite Clay⁸ 0.275 Water 825Water/Cementitious Materials Ratio 0.30 Sand/Cementitious MaterialsRatio 1.15 Superplasticizer/Cementitious Materials, wt % 0.5%  PotassiumCitrate/Cementitious Materials, wt %  2% Calcium SulfoaluminateCement/Fly ash, wt % 20% Calcium Sulfate/Calcium Sulfoaluminate 50%Cement, wt % ¹Class C Fly Ash, Campbell Power Plant, West Olive, MI ²USGTerra Alba Filler ³FASTROCK 500, CTS Company ⁴UNIMIN 5030 Sand ⁵BASFCASTAMENT FS20 ⁶SURFYNOL 500S ⁷MOMENTIVE AXILAT RH 100 XP ⁸BENTONE CTHECTORITE clay

The mixture compositions investigated in this example had good rheologyand yielded a slump of 10¼ in the slump test. The slump patty for thismixture composition after drying remained in excellent condition and didnot develop any cracking.

Shrinkage Behavior

FIG. 27A shows shrinkage behavior of geopolymer cementitious compositionof the embodiment of the invention investigated in Example 29.

The shrinkage measurements were initiated at an age of about 4-hoursfrom the time the raw materials were mixed together to form an aqueousslurry. The material shrinkage was measured for a total duration ofabout 8-weeks while curing the material at about 75° F./50% RH.

The following important conclusions can be drawn from this investigationand FIG. 27A:

Contrary to the shrinkage bars of comparative Example 4 (with no calciumsulfate) which cracked even before de-molding, the shrinkage bars ofExample 29 comprising calcium sulfate dihydrate were completely stableand did not result in any cracks either prior to or after de-molding.

The geopolymer cementitious composition of the embodiment of theinvention comprising fly ash, calcium sulfoaluminate cement, calciumsulfate dihydrate, and alkali metal citrate investigated in this examplehad a maximum shrinkage of only about 0.04% in comparison to a maximumshrinkage of about 0.75% for the comparative mixture compositioncontaining fly ash and alkali metal citrate only (Example 1).

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 27B shows the exothermic and slurry temperature rise behavior ofgeopolymer cementitious composition of the embodiment of the inventioninvestigated in Example 29. This cementitious composition demonstratedvery moderate temperature rise behavior with the maximum slurrytemperature reaching only 108° F.

A moderate heat evolution and low temperature rise within the materialduring the curing stage assists in preventing excessive thermalexpansion and consequent cracking and disruption of material. Thisaspect becomes even more helpful when the material is utilized in amanner where large thicknesses of material pours are involved in theactual field applications. The geopolymer cementitious composition ofthis embodiment of the invention will be highly beneficial in thisparticular aspect as it would lead to a lower thermal expansion andenhanced resistance to thermal cracking in field applications.

Time of Setting

TABLE 98 shows the time of setting of geopolymer cementitiouscompositions of some embodiments of the invention investigated inExample 29. These results embodiments of the invention and yetparticulary useful in self-leveling underlayment applications.

TABLE 98 Setting Times of Example 30 Initial Setting Time Final SettingTime (hr:min) (hr:min) 1:02 1:18

Compressive Strength

TABLE 99 shows the compressive strength behavior of the developedgeopolymer cementitious composition of the embodiment of the inventioninvestigated in this example. These results demonstrate the suitabilityof the geopolymer compositions of this invention for use in theself-leveling underlayment applications.

TABLE 99 Compressive Strength of Example 30 (psi) 4-hour 24 hour 7 day28 day Mix 1 2231 3954 4173 4890

Example 31

This example demonstrates the unique behavior and mechanical performanceof lightweight geopolymer binder compositions of some embodiments of theinvention.

TABLE 100 shows the raw material compositions of the lightweightgeopolymer cementitious mixtures investigated in this example.

TABLE 100 Compositions investigated in Example 31 Raw Material Mix #1Mix 2 Mix 3 Fly Ash Class C¹ (grams) 4923 5577 6154 Calcium SulfateDihydrate² 492 558 615 (grams) Calcium Sulfoaluminate 985 1115 1231Cement³ (grams) Total Cementitious Materials 6400 7250 8000 (grams)Lightweight Filler⁴ (grams) 2016 1740 1480 Potassium Citrate Monohydrate128 145 160 Superplasticizer⁵ (grams) 32.00 36.25 40.00 Defoamer &Wetting Agent⁶ 12.8 18.1 16.0 Rheology Modifier⁷ 0.38 0.44 0.48 LithiumCarbonate 16 18.1 20 Colorant⁸ 4.8 5.44 6 Water (grams) 2045 750 2040Water/Cementitious Materials 0.32 0.28 0.255 Ratio LightweightFiller/Cementitious 0.315 0.24 0.185 Materials RatioSuperplasticizer/Cementitious 0.5%  0.5%  0.5%  Materials, wt %Potassium Citrate/Cementitious  2%  2%  2% Materials, wt % CalciumSulfoaluminate 80% 80% 80% cement/Fly ash, wt % Calcium Sulfate/Calcium50% 10% 20% Sulfoaluminate Cement, wt % ¹Class C Fly Ash, Campbell PowerPlant, West Olive, MI ²USG Terra Alba Filler ³FASTROCK 500, CTS Company⁴Poraver Hollow Recycled Glass Microspheres 0.04-0.125 mm ⁵BASFCASTAMENT FS20 ⁶SURFYNOL 500S ⁷MOMENTIVE AXILAT RH 100 XP ⁸Yipin BlackS350M Iron Oxide PigmentThe measured density of the lightweight geopolymer compositionsinvestigated in this example was as follows:

-   Mix #1: 96 pcf-   Mix #2: 101 pcf-   Mix #3: 105 pcf

Slump and Early Age Cracking Behavior of Material

TABLE 101 shows the slump behavior of the lightweight geopolymercementitious compositions of some embodiments of the inventioninvestigated in this example.

TABLE 101 Flow and Slump of Example 31 Slump (inches) Mix 1 9⅝″ Mix 28¾″ Mix 3 8″

All mixture compositions investigated had good rheology and slumpbehavior as observed in the slump test. It is particularly noteworthythat such good rheology and slump behavior was obtainable even at awater/cementitious materials ratio as low as about 0.255.

All slump patties of the mixes investigate in the example were inexcellent condition and did not develop any cracking.

Heat Evolution and Slurry Temperature Rise Behavior

FIG. 28 shows the exothermic and slurry temperature rise behavior of thelightweight geopolymer cementitious compositions of some embodiments ofthe invention investigated in Example 31. It can be observed that thesecompositions demonstrated very low temperature rise behavior. A moderateheat evolution and low temperature rise within the material during thecuring stage are significant in assisting to prevent excessive thermalexpansion and consequent cracking and disruption of material. Thisaspect becomes even more helpful when the material is utilized in amanner where large thicknesses of material pours are involved in theactual field applications. The geopolymer cementitious compositions ofsome embodiments of the invention investigated in this example aredisclosed to be highly beneficial in this particular aspect as theywould lead to a lower thermal expansion and enhanced resistance tothermal cracking in actual field applications.

Time of Setting

TABLE 102 shows the time of setting of the lightweight geopolymercementitious compositions of the embodiments of the inventioninvestigated in this example. It can be observed that all cementitiouscompositions investigated in this example demonstrated a rapid settingbehavior with the final setting time ranging between 1 to 2 hours.

TABLE 102 Setting Times of Example 31 Initial Setting Time Final SettingTime (hr:min) (hr:min) Mix 1 1:22 1:55 Mix 2 1:08 1:28 Mix 3 1:03 1:11

Compressive Strength

TABLE 103 shows the compressive strength behavior of the lightweightgeopolymer cementitious compositions of the embodiments of the inventioninvestigated in Example 31.

TABLE 103 Compressive Strength of Example 31 (psi) 4 hour 24 hour 7 day28 day Mix 1 1110 2761 3466 4044 Mix 2 1478 3232 4873 5653 Mix 3 22504227 4432 5735

The following observations can be drawn from this study:

Both the early age compressive strength and the ultimate compressivestrength of the lightweight geopolymer compositions of this inventionare relatively very high and comparable to some of the full densitycompositions of the present invention (compare results from Example 30with those of Example 31).

It is noteworthy that the 4-hour compressive strengths of lightweightgeopolymer compositions of the invention investigated in this exampleare in excess of about 1000 psi.

It is also noteworthy that the 24-hour compressive strengths of thelightweight geopolymer compositions of this invention in excess of about2500 psi.

It is again very noteworthy that the 28-day compressive strengths of thelightweight geopolymer cementitious compositions of the invention arevery high i.e. in excess of about 4000 psi.

The geopolymer compositions of some preferred embodiments of theinvention shown in the examples have application in a number ofcommercial products. In particular the compositons can be used for;

Road repair and road patch products, traffic bearing surfaces andpavements, as shown by some properties disclosed in examples 5, 24, 25,and 31;

Bricks and synthetic stones, as shown by some properties disclosed inexamples 5, 6, 9, 12 and 14;

Repair materials for wall, floors and ceiling and bonding mortars,plasters and panel surfacing materials, as shown by some propertiesdisclosed in examples 5, 24 and 33;

Roofing materials, as shown by some properties disclosed in examples 5,26, 30 and 31;

Shotcrete products which are sprayed cementitious products used for soiland rock stabilization and as lining materials, as shown by someproperties disclosed in examples 5, 25 and 30;

Weight bearing structures, as shown by some properties disclosed inexamples 25, 30, and 31;

Statuaries and architectural moldings, as shown by some propertiesdisclosed in examples 5-22, 29, 30; and 31;

Self leveling underlayments, as shown by some properties disclosed inexamples 5, 7, 9, 13, 15, 19, 21, 22, 24, 26, 30, and 31.

Although we have described the preferred embodiments for implementingour invention, it will be understood by those skilled in the art towhich this disclosure is directed that modifications and additions maybe made to our invention without departing from its scope.

What is claimed is:
 1. An aluminosilicate geopolymer compositioncomprising the reaction product of: a cementitious reactive materialcomprising: about 33 to about 97% by weight a thermally activatedaluminosilicate mineral comprising Class C fly ash, about 1 to about 43%by weight a calcium sulfoaluminate cement, about 1 to about 40% byweight a calcium sulfate selected from the group consisting of calciumsulfate dihydrate, calcium sulfate hemihydrate, anhydrous calciumsulfate and mixtures thereof; and a chemical activator in an amountequal to about 1.0 to about 6.0% by weight of the cementitious reactivematerial, the chemical activator selected from at least one member ofthe group consisting of alkali metal citrates; and water, wherein thecalcium sulfate has an average particle size from about 1 to about 100microns.
 2. The aluminosilicate geopolymer composition of claim 1,wherein the cementitious reactive material comprises about 33 to about97% by weight Class C fly ash, about 1 to about 40% by weight saidcalcium sulfoaluminate cement, about 1 to about 40% by weight saidcalcium sulfate wherein the chemical activator is selected from at leastone member of the group consisting of an potassium citrate and sodiumcitrate.
 3. The composition of claim 1, wherein the chemical activatoris selected from at least one member of the group consisting of sodiumcitrate and potassium citrate.
 4. The composition of claim 1, whereinthe composition has an absence of Portland cement.
 5. The composition ofclaim 1, wherein the amounts of the chemical activator and calciumsulfate relative to the amounts of thermally activated aluminosilicatemineral and calcium sulfoaluminate cement are effective to cause thereaction product to set in about 120 minutes or less after mixing withwater.
 6. The composition of claim 1, wherein the cementitious reactivematerial comprises: about 41 to about 67% by weight Class C fly ash,about 18 to about 43% by weight calcium sulfoaluminate cement, and about4 to about 36% by weight calcium sulfate; wherein the amount of chemicalactivator equals about 2 to about 5.0% by weight of the cementitiousreactive powder, wherein the chemical activator is selected from atleast one member of the group consisting of sodium citrate and potassiumcitrate.
 7. The composition of claim 6, wherein the amount of calciumsulfoaluminate cement relative to the amounts of chemical activator,calcium sulfate and thermally activated aluminosilicate mineral iseffective to cause the reaction product to set in about 120 minutes orless after mixing with water.
 8. The composition of claim 1, wherein theamount of calcium sulfoaluminate cement, calcium sulfate and chemicalactivator relative to the amount of thermally activated aluminosilicatemineral is effective to limit shrinkage of the composition to less thanabout 0.3%.
 9. The composition of claim 1, wherein the chemicalactivator is present in an amount equal to about 1.25 to 4.00% by weightbased on total weight of the cementitious reactive powder; wherein thechemical activator is selected from at least one member of the groupconsisting of sodium citrate and potassium citrate.
 10. The compositionof claim 1, wherein the reaction product is formed from the water, thecementitious reactive material comprising about 60% to about 90% byweight said thermally activated aluminosilicate mineral comprising ClassC fly ash; about 4% to about 35% by weight said calcium sulfoaluminatecement, and about 4.0% to about 15% by weight said calcium sulfate, andthe chemical activator, wherein the amount of chemical activator equalsabout 1.25 to 4.00% by weight of the cementitious reactive material. 11.The composition of claim 1, wherein the reaction product is formed fromthe water; the cementitious reactive material comprising about 60% toabout 85% by weight of the thermally activated mineral comprising ClassC fly ash, about 8% to about 30% by weight calcium sulfoaluminatecement, and about 4.0% to about 15% by weight calcium sulfate, and thechemical activator, wherein the amount of chemical activator equalsabout 1.5 to 3.00% by weight of the cementitious reactive material. 12.The composition of claim 1, further comprising lithium carbonate. 13.The composition of claim 1, having a 4-hour compressive strength fromabout 1000 psi (6.9 MPa) to about 2500 psi (17.2 MPa).
 14. Thecomposition of claim 1, having a 24-hour compressive strength about 1500psi (10.3 MPa) to about 3500 psi (24.1 MPa).
 15. The composition ofclaim 1, having a 28-day compressive strength from about 3500 psi (24.1MPa) to about 10000 psi (69 MPa).
 16. The composition of claim 1, havinga water saturated compressive strength at 28-days from about 3500 psi(24.1 MPa) to about 10000 psi (69 MPa).
 17. The composition of claim 1,wherein the calcium sulfate comprises calcium sulfate hemihydrate. 18.The composition of claim 1, wherein the calcium sulfate comprisescalcium sulfate dehydrate.
 19. The composition of claim 1, wherein thecalcium sulfate comprises anhydrous calcium sulfate.
 20. The compositionof claim 1, wherein the composition has a tensile bonding strength tosubstrates in excess of 200 psi.
 21. The composition of claim 1, whereinthe composition further comprises a filler.
 22. The composition of claim1, wherein the reaction product results from an exothermic reaction in awater slurry, wherein the amount of calcium sulfoaluminate cement,calcium sulfate and chemical activator relative to the amount ofthermally activated aluminosilicate mineral is effective to limit themaximum slurry temperature rise to about 50° F. or less, wherein theamount of chemical activator equals about 1.25 to about 4% by weight ofthe cementitious reactive material.
 23. The composition of claim 22,wherein the maximum slurry temperature rise is limited to less thanabout 40° F.
 24. The composition of claim 22, wherein the cementitiousreactive material comprises: about 41 to about 67% by weight saidthermally activated aluminosilicate mineral comprising Class C fly ash,about 18 to about 43% by weight said calcium sulfoaluminate cement, andabout 4 to about 36% by weight said calcium sulfate, wherein the amountof the chemical activator equals about 2 to about 5.0% by weight of thecementitious reactive material.
 25. The composition of claim 1, whereinthe weight ratio of the mixture to water is less than about 0.4.
 26. Thecomposition of claim 1, wherein the weight ratio of the mixture to wateris less than about 0.3.
 27. A settable mixture for forming analuminosilicate geopolymer composition when reacted in water,comprising: a cementitious reactive material comprising: about 33 toabout 97% by weight of a thermally activated aluminosilicate mineralcomprising Class C fly ash; about 1 to about 43% by weight of a calciumsulfoaluminate cement, about 1 to about 40% by weight of a calciumsulfate selected from the group consisting of calcium sulfate dihydrate,calcium sulfate hemihydrate, anhydrous calcium sulfate and mixturesthereof; and a chemical activator selected from at least one member ofthe group consisting of alkali metal citrates, wherein the chemicalactivator is present in an amount equal to about 1.0 to about 6.0% byweight of the cementitious reactive material.
 28. The aluminosilicategeopolymer composition formed from the reaction of the mixture of claim27 in water, wherein shrinkage of the composition is less than about0.3%.
 29. The aluminosilicate geopolymer compositon formed from thereaction of the mixture of claim 28 in water, wherein shrinkage of thereaction product is less than about 0.05%.
 30. The aluminosilicategeopolymer composition of claim 29, wherein the composition has anabsence of Portland cement.
 31. The aluminosilicate geopolymercomposition formed from the reaction of the mixture of claim 30 inwater, wherein the aluminosilicate geopolymer composition has 4-hourcompressive strength of from about 1000 psi (6.9 MPa) to greater thanabout 2500 psi (17.2 MPa); 24-hour compressive strength of about 1500psi (10.3 MPa) to greater than about 3500 psi (24.1 MPa)a), and 28-daycompressive strength of about 3500 psi (24.1 MPa) to about 10000 psi (69MPa) and wherein the mixture has a set time of less than about 10minutes to about 120 minutes after reacting the mixture in water. 32.The aluminosilicate geopolymer composition formed from the reaction ofthe mixture of claim 31 in water, wherein the aluminosilicate geopolymercomposition has a controlled exothermic reaction with a maximum slurrytemperature rise of less than about 50° F.
 33. The aluminosiicategeopolymer composition reaction of claim 32, wherein the cementitiousreactive material comprises: about 41 to about 67% by weight said ClassC fly ash, about 18 to about 43% by weight said calcium sulfoaluminatecement, and about 4 to about 36% by weight said calcium sulfate, whereinthe chemical activator is selected from at least one member of the groupconsisting of potassium citrate and sodium citrate; wherein the amountof chemical activator equals about 2 to about 5.0% by weight of thecementitious reactive material.
 34. The aluminosilicate aluminosiilcatogeopolymer composition formed from the reaction of the mixture of claim27 with water, wherein the weight ratio of the mixture to water is lessthan about 0.4.
 35. The aluminosilicate geopolymer composition formedfrom the reaction of the mixture of claim 27 with water, wherein thechemical activator is present in an amount equal to about 1.25 to 4.00%by weight based on total weight of the cementitious reactive powder;wherein the chemical activator is selected from at least one member ofthe group consisting of sodium citrate and potassium citrate.
 36. Thecomposition of claim 1, forming a construction repair material.
 37. Thecomposition of claim 1, forming a floor repair material.
 38. Thecomposition of claim 1, forming a self leveling floor underlayment overa substrate.
 39. The composition of claim 1, forming a load bearingstructure.
 40. The composition of claim 1, forming a panel surfacingmaterial.
 41. The composition of claim 1, in the form of a binder inconstruction materials.
 42. The composition of claim 1, in the form ofconstruction materials selected from the group consisting of brick,blocks and stones.
 43. The composition of claim 1, forming a wallsurfacing material.
 44. The composition of claim 1, forming a pavementmaterial for traffic bearing surfaces.
 45. The composition of claim 1,forming a repair material for traffic bearing surfaces.
 46. Thecomposition of claim 1, in the form of a material for weight bearingstructures.
 47. The composition of claim 1, in the form of a roofingmaterial.
 48. The composition of claim 1, in the form of a shotcretematerial.
 49. The composition of claim 1, in the form of a mortar.
 50. Amethod of preparing an aluminosilicate geopolymer composition of claim1, comprising: reacting a cementitious reactive material comprising:about 33 to about 97 parts by weight a thermally activatedaluminosilicate mineral comprising Class C fly ash, about 1 to about 43parts by weight a calcium sulfoaluminate cement, about 1 to about 40parts by weight a calcium sulfate selected from the group consisting ofcalcium sulfate dihydrate, calcium sulfate hemihydrate, anhydrouscalcium sulfate, and mixtures thereof; and a chemical activator selectedfrom at least one member of the group consisting of alkali metalcitrates, wherein the chemical activator is present in an amount equalto about 1.0 to about 6.0% by weight of the cementitious reactivematerial; and water.
 51. The method of claim 50, wherein thecementitious reactive material comprises about 33 to about 97 parts byweight class C fly ash about 1 to about 40 parts by weight said calciumsulfoaluminate cement, about 1 to about 40 parts by weight said calciumsulfate, wherein the chemical activator is selected from at least onemember of the group consisting of potassium citrate and sodium citrate.52. The method of claim 50, wherein the chemical activator is present inan amount equal to about 1.25 to 4.00% by weight based on total weightof the cementitious reactive powder; wherein the chemical activator isselected from at least one member of the group consisting of sodiumcitrate and potassium citrate.
 53. The method of claim 52, wherein thecompositon has an absence of Portland cement.
 54. The composition ofclaim 1, wherein the amount of chemical activator equals about 1.25 toabout 4% by weight of the cementitious reactive material, and whereinthe calcium sulfate comprises calcium sulfate hemihydrate.
 55. Themixture of claim 27, wherein the chemical activator is selected from atleast one member of the group consisting of potassium citrate and sodiumcitrate.
 56. The method of claim 50, wherein the chemical activator isselected from at least one member of the group consisting of potassiumcitrate and sodium citrate.